Q&A Hero

Q: Regional Manager Sue Collins would like to know if the mean number of telephone calls made per 8-hour shift is the same for the telemarketers at her three call centers (Austin, Las Vegas, and Albuquerque). A simple random sample of 6 telemarketers from each of the three call centers was taken and the number of telephone calls made in eight hours by each observed employee is shown below.ObservationCenter 1 AustinCenter 2 Las VegasCenter 3 Albuquerque182727126863813777473480606856970766787380Sample Mean75.66768.66774.833Sample Variance33.86733.46726.167Using = .10, test for any significant difference in the mean number of telephone calls made at the three call centers.

Q: A survey was recently conducted to determine if consumers spend more on computer-related purchases via the Internet or store visits. Assume a sample of 8 respondents provided the following data on their computer-related purchases during a 30-day period. Using a .05 level of significance, can we conclude that consumers spend more on computer-related purchases by way of the Internet than by visiting stores?Expenditures (dollars)RespondentIn-StoreInternet11322252902431199541655585136248105764578490

Q: A manager is thinking of providing, on a regular basis, in-house training for employees preparing for an inventory management certification exam. In the past, some employees received the in-house training before taking the exam, while others did not. Independent random samples taken from the company's records provided the following exam scores for 10 workers who did not receive in-house training and 8 workers who did receive training. (The manager is confident that the distributions of both populations' exam scores are approximately normal.)No TrainingTraining7680806660719179739477748283687875 86 a. Develop a 95% confidence interval estimate for the difference between the average test scores for the two populations of employees.b. Using = .05, test for any difference between the average test scores for the two populations of employees.

Q: Starting annual salaries for business school graduates majoring in finance and management information systems (MIS) were collected in two independent random samples. Use the following data to develop a 95% confidence interval estimate of the difference between the starting salaries for the two majors. Based on previous studies, the population standard deviations for Finance and MIS salaries are estimated to be $2,100 and $2,600, respectively. Finance MIS n1 = 60 n2 = 50 = $43,200 = $46,500

Q: The following independent samples show the delivery times for two suppliers of raw materials (in days). A company currently uses Supplier A but will switch to Supplier B if its average delivery time is less than that for Supplier A. Use Excel to conduct the appropriate hypothesis test. Use = .10.Supplier ASupplier B10123613131541214761410241481816128201810129458

Q: Independent samples of commuters are taken from two cities. The following data represents the time (in minutes) to drive to work. Use Excel to determine whether the average commuting times are significantly different between the two cities. Use = .05.City ACity B15.2540.2512.7548.7525.5050.0012.5012.2518.7545.0015.5010.0060.2516.7522.7542.0010.5018.7538.7542.5010.5028.5045.0012.2535.7530.00

Q: At a particular airport in the United States, independent samples of domestic flights from two airlines were taken and the amount of time each flight was delayed was measured. The results follow.Minutes Delayed Airline AMinutes Delayed Airline B0.033.70.07.225.631.80.034.638.936.20.041.627.324.734.843.144.50.038.939.441.841.542.17.835.323.539.512.834.538.135.733.029.032.941.331.8Use Excel to estimate the difference in average delay time between the two airlines with a 95% level of confidence.

Q: Independent random samples of Company W employees were taken to compare salaries between college graduates and high school graduates. Samples of size 30 were taken for each group. The results follow.Salary HS ($1000)Salary College ($1000)24.122.924.032.433.126.221.219.923.930.929.628.725.719.529.039.232.131.828.822.124.729.630.428.528.622.724.435.530.432.730.218.623.532.031.328.618.423.330.932.033.333.524.323.827.628.337.541.428.325.432.130.835.428.421.723.923.031.237.227.2Use Excel to estimate the difference in average salaries between the two groups with a 95% level of confidence.

Q: In a completely randomized experimental design, 16 experimental units were used for each of the 4 levels of the factor (i.e., 4 treatments). Part of the ANOVA table is shown below.ANOVASource of VariationSSdfMSFBetween Groups??100?Within Groups???Total1560?a. Determine all the missing values in the above table and fill in the blanks.b. Use = 0.05 to determine if there is any significant difference among the means of the four groups.

Q: Samples were selected from three populations. The data obtained are shown below.Sample 1Sample 2Sample 310161591415121316131414161017Sample Mean ()111514Sample Variance ()3.332.45.5a. Compute the overall sample mean .b. Set up an ANOVA table for this problem.c. At 95% confidence test to determine whether there is a significant difference in the means of the three populations.

Q: In a completely randomized experimental design, 11 experimental units were used for each of the 4 treatments. Part of the ANOVA table is shown below.ANOVASource of VariationSSdfMSFBetween Groups1500???Within Groups???Total5500?a. Determine all the missing values in the above table and fill in the blanks.b. Use = 0.05 to determine if there is any significant difference among the means of the four treatments.

Q: MOA, Inc. has three stores located in three different areas. Random samples of the sales of the three stores (In $1,000) are shown below.Store 1Store 2Store 3463433473631453535423945a. Compute the overall sample mean .b. At 95% confidence, test to see if there is a significant difference in the average sales of the three stores. Show the complete ANOVA table.

Q: Three different brands of tires were compared for wear characteristics. From each brand of tire, ten tires were randomly selected and subjected to standard wear-testing procedures. The average mileage obtained for each brand of tire and sample variances (both in 1,000 miles) are shown below.Brand ABrand BBrand CAverage Mileage373833Sample variance342At 95% confidence, test to see if there is a significant difference in the average mileage of the three brands.

Q: Random samples of individuals from three different cities were asked how much time they spend per day watching television. The results (in minutes) for the three groups are shown below.City ICity IICity III260182211280190190240220247260240300a. Compute the overall sample mean .b. At = 0.05, test to see if there is a significant difference in the averages of the three groups. Show the complete ANOVA table.

Q: Eight observations were selected from each of 3 populations (total of 24 observations), and an analysis of variance was performed on the data. The following are part of the results.ANOVASource of VariationSSdfMSFBetween Groups216???Within Groups252??Total??Using = .05, test to see if there is a significant difference among the means of the three populations.

Q: The following are the results from a completely randomized design consisting of 3 treatments.ANOVASource of VariationSSdfMSFBetween Groups390???Within Groups???Total55823Using = .05, test to see if there is a significant difference among the means of the three populations.

Q: Ten observations were selected from each of 3 populations, and an analysis of variance was performed on the data. The following are the results.ANOVASource of VariationSSdfMSFBetween Groups82???Within Groups162??Total??At 95% confidence, test to see if there is a significant difference among the means of the three populations.

Q: MNM, Inc. has three stores located in three different areas. Random samples of the daily sales of the three stores (in $1,000) are shown below.Store 1Store 2Store 391068117710881311At 95% confidence, test to see if there is a significant difference in the average sales of the three stores. Show the complete ANOVA table.

Q: Part of an ANOVA table involving 8 groups for a study is shown below.ANOVASource of VariationSSdfMSFBetween Groups126???Within Groups240??Total?67a. Determine all the missing values in the above table and fill in the blanks.b. Use = 0.05 to determine if there is any significant difference among the means of the eight groups.

Q: Part of an ANOVA table is shown below.ANOVASource of VariationSSdfMSFBetween Groups903??Within Groups120??Total?23a. Determine the missing values and fill in the blanks in the above table. At 95% confidence, test to determine if there is a significant difference among the means.b. How many groups have there been in this problem?c. What has been the total number of observations?

Q: The three major automobile manufacturers have entered their cars in the Indianapolis 500 race. The speeds of the tested cars are given below.Manufacturer AManufacturer BManufacturer C180177175175180176179167177176172190a. Compute the overall sample mean .b. At = .05, test to see if there is a significant difference in the average speeds of the cars of the auto manufacturers. Show the complete ANOVA table.

Q: Three universities in your state decided to administer the same comprehensive examination to the recipients of MBA degrees from the three institutions. From each institution, MBA recipients were randomly selected and were given the test. The following table shows the scores of the students from each university.Northern UniversityCentral UniversitySouthern University748579768580848683858878818284a. Compute the overall sample mean .b. At = 0.05, test to see if there is any significant difference in the average scores of the students from the three universities. (Note that the sample sizes are not equal.)

Q: The heating bills for a selected sample of houses using various forms of heating are given below (values are in dollars).Gas Heated HomesCentral ElectricHeat Pump839081808883828780838282828379At = 0.05, test to see if there is a significant difference among the average bills of the homes. Show the complete ANOVA table.

Q: Random samples of employees from three different departments of MNM Corporation showed the following yearly incomes (in $1,000).Department ADepartment BDepartment C454650404148434348393350354147384245At = .05, test to determine if there is a significant difference among the average incomes of the employees from the three departments. Show the complete ANOVA table.

Q: Individuals were randomly assigned to three different production processes. The hourly units of production for the three processes are shown below.Process 1Process 2Process 3333328303536283030293834Use the analysis of variance procedure with = 0.05 to determine if there is a significant difference in the mean hourly units of production for the three types of production processes. Show the complete ANOVA table.

Q: The final examination grades of random samples of students from three different classes are shown below.Class AClass BClass C929185858593969082998684At the = .05 level of significance, is there any difference in the mean grades of the three classes? Show the complete ANOVA table.

Q: For four populations, the population variances are assumed to be equal. Random samples from each population provide the following data.PopulationSample SizeSample MeanSample Variance1114023.42113521.63113925.24113724.6Using a .05 level of significance, test to see if the means for all four populations are the same. Show the complete ANOVA table.

Q: Ziba Corporation wants to increase the productivity of its line workers. Four different programs have been suggested to help increase productivity. Twenty employees, making up a sample, have been randomly assigned to one of the four programs and their output for a day's work has been recorded. You are given the results below.Program AProgram BProgram CProgram D150150185175130120220150120135190120180160180130145110175175a. State the null and alternative hypotheses.b. Construct an ANOVA table.c. At 95% confidence, test to determine if the means of the three populations are equal.

Q: A dietician wants to see if there is any difference in the effectiveness of three diets. Eighteen people were randomly chosen for the test. Then each individual was randomly assigned to one of the three diets. Below you are given the total amount of weight lost in a six-month period by each person.Diet ADiet BDiet C141225181032202218121214201617181214a. State the null and alternative hypotheses.b. Prepare an ANOVA.c. At 95% confidence test to determine if there is a significant difference in the means of the three populations.

Q: In order to test to see if there is any significant difference in the mean number of units produced per week by each of three production methods, the following data were collected:Method IMethod IIMethod III182170160170192156185190179a. Compute the overall sample mean .b. At the = 0.05 level of significance, is there any difference in the mean number of units produced per week by each method?Show the complete ANOVA table. Note that the sample sizes are not equal.

Q: At = 0.05, test to determine if the means of the three populations (from which the following samples are selected) are equal. Show the complete ANOVA table.Sample 1Sample 2Sample 3608460787857729369668166

Q: Three different models of automobiles (A, B, and C) were compared for gasoline consumption. For each model of car, ten cars were randomly selected and subjected to standard driving procedures. The average miles/gallon obtained for each model of car and sample standard deviations are shown below.Car ACar BCar CAverage Mile/Gallon424944Sample Standard Deviation453Use the above data and test to see if the mean gasoline consumption for all three models of cars is the same. Let a= 0.05. Show the complete ANOVA table.

Q: In order to compare the life expectancies of three different brands of printers, eight printers of each brand were randomly selected. Information regarding the three brands is shown below.Brand ABrand BBrand CAverage life (in months)625260Sample variance362549Use the above data and test to see if the mean life expectancies of the three brands are the same. Let = 0.05. Show the complete ANOVA table.

Q: Wendy, Inc. has three stores located in three different areas. Random samples of the sales of the three stores (in $1,000) are shown below.Store 1Store 2Store 3937685857467886064827092a. Compute the overall sample mean .b. At 95% confidence, test to see if there is a significant difference in the average sales of the three stores. Note that the sample sizes are not equal. Show your complete work and the ANOVA table.

Q: In a completely randomized experimental design, 11 experimental units were used for each of the 3 treatments. Part of the ANOVA table is shown below.ANOVASource of VariationSSdfMSFBetween Groups1500???Within Groups???Total600032a. Fill in the blanks in the above ANOVA table.b. At 95% confidence, test to determine whether or not the means of the 3 populations are equal.

Q: Three universities administer the same comprehensive examination to the recipients of MS degrees in psychology. From each institution, a random sample of MS recipients was selected, and these recipients were then given the exam. The following table shows the scores of the students from each university.University AUniversity BUniversity C896075959570758990928078996677a. Compute the overall sample mean .b. At = 0.05, test to see if there is any significant difference in the average scores of the students from the three universities. Set up the complete ANOVA table (Note that the sample sizes are not equal.)

Q: The test scores for selected samples of statistics students who took the course from three different instructors are shown below.Instructor AInstructor BInstructor C819085625590828490879195738580At = 0.05, test to see if there is a significant difference among the averages of the three groups. Show the complete ANOVA table.

Q: Six observations were selected from each of three populations. The data obtained is shown below.Sample 1Sample 2Sample 3313137283236343339323040263235293435a. Compute the overall sample mean .b. Test at the = 0.05 level to determine if there is a significant difference in the means of the three populations.

Q: The manager of Roth Corporation wants to determine whether or not the type of work schedule for her employees has any effect on their productivity. She has selected 15 production employees at random and then randomly assigned 5 employees to each of the 3 proposed work schedules. The following table shows the units of production (per week) under each of the work schedules.Work Schedule (Treatments)Schedule 1Schedule 2Schedule 3506075606575706555405840455755a. Compute the overall sample mean .b. At 95% confidence, determine if there is a significant difference in the mean weekly units of production for the three types of work schedules.

Q: Random samples were selected from three populations. The data obtained are shown below.Treatment 1Treatment 2Treatment 3453139413437373538404042a. Compute the overall sample mean .b. At 90% confidence, test to see if there is a significant difference in the means of the three populations. Show the complete ANOVA table. Please note that the sample sizes are not equal.

Q: In a completely randomized experimental design, 7 experimental units were used for the first treatment, 9 experimental units for the second treatment, and 14 experimental units for the third treatment. Part of the ANOVA table for this experiment is shown below.ANOVASource of VariationSSdfMSFBetween Groups???4.5Within Groups??4Total??a. Fill in allthe blanks in the above ANOVA table.b. At 95% confidence, test to see if there is a significant difference among the means.

Q: Random samples were selected from three populations. The data obtained are shown below.Treatment 1Treatment 2Treatment 3374328333932363533383840a. Compute the overall sample mean .b. At 95% confidence, test to see if there is a significant difference in the means of the three populations. Show the complete ANOVA table. Please note that the sample sizes are not equal.

Q: In a completely randomized experimental design, 18 experimental units were used for the first treatment, 10 experimental units for the second treatment, and 15 experimental units for the third treatment. Part of the ANOVA table for this experiment is shown below.ANOVASource of VariationSSdfMSFBetween Groups???3Within Groups??6Total??

Q: Guitars R. US has three stores located in three different areas. Random samples of the sales of the three stores (in $1000) are shown below. Store 1Store 2Store 38085797586857681888980 80 a. Compute the overall sample mean .b. At 95% confidence, test to see if there is a significant difference in the average sales of the three stores. Set up the complete ANOVA table. Please note that the sample sizes are not equal.

Q: Information regarding the ACT scores of samples of students in four different majors is given below.MajorManagementMarketingFinanceAccounting2922292827222726212527252826282022272421282020192823202723253024282729212428232927312724Sum318245234312Mean26.5024.5026.0024.00Variance10.096.9414.509.00a. Set up the ANOVA table for this problem.b. At 95% confidence, test to determine whether there is a significant difference in the means of the three populations.

Q: Information regarding the ACT scores of samples of students in three different majors is given below.MajorManagementFinanceAccounting2822292623272524262722282124251926262727281729201728202324282829Sums230225338Means232526Variances186.759.33a. Set up the ANOVA table for this problem.b. At 95% confidence test to determine whether there is a significant difference in the means of the three populations.

Q: The following information was obtained from matched samples regarding the productivity of four individuals using two different methods of production.IndividualMethod 1Method 2168295376475586695763Let d = Method 1 -Method 2. Is there a significant difference between the productivity of the two methods? Let = 0.05.

Q: A company attempts to evaluate the potential for a new bonus plan by selecting a sample of 4 salespersons to use the bonus plan for a trial period. The weekly sales volume before and after implementing the bonus plan is shown below. (For the following matched samples, let the difference "d" be d = after -before.)Weekly SalesSalespersonBeforeAfter14448240483363845044a. State the hypotheses.b. Compute the test statistic.c. Use Alpha = .05 and test to see if the bonus plan will result in an increasein the mean weekly sales.

Q: Allied Corporation is trying to determine whether to purchase Machine A or B. It has leased the two machines for a month. A random sample of 5 employees has been taken. These employees have gone through a training session on both machines. Below you are given information on their productivity rate on both machines. (Let d = Machine A - Machine B.)Productivity RatePersonMachine AMachine B1475225358350474556054553a. State the null and alternative hypotheses for a two-tailed test.b. Find the mean and standard deviation for the difference.c. Compute the test statistic.d. Test the null hypothesis stated in Part a at the 10% level.

Q: The following shows the monthly sales in units of six salespersons before and after a bonus plan was introduced. At 95% confidence, determine whether the bonus plan has increased sales significantly. (For the following matched samples, let the difference "d" be: d = after before.)Monthly SalesSalespersonAfterBefore194902828439084476705798068580

Q: A test on world history was given to a group of individuals before and also after a film on the history of the world was presented. The results are given below. We want to determine if the film significantly increased the test scores. (For the following matched samples, let the d = after -before.)IndividualAfterBefore19286286883898449090593856889079791a. Give the hypotheses for this problem.b. Compute the test statistic.c. At 95% confidence, test the hypotheses.

Q: The following data present the number of computer units sold per day by a sample of 6 salespersons before and after a bonus plan was implemented. Let d = before " after.SalespersonBeforeAfter136275366487578698At 95% confidence, test to see if the bonus plan was effective. That is, did the bonus plan actually increasesales?

Q: The daily production rates for a sample of factory workers before and after a training program are shown below. Let d= After " Before.WorkerBeforeAfter1692101239104811579We want to determine if the training program was effective.a. Give the hypotheses for this problem.b. Compute the test statistic.c. At 95% confidence, test the hypotheses. That is, did the training program actually increasethe production rates?

Q: In order to determine whether or not a driver's education course improves the scores on a driving exam, a sample of 6 students were given the exam before and after taking the course. The results are shown below.Let d= Score After -Score Before.ScoreScoreStudentBefore the CourseAfter the Course183872898839391477775869367983a. Compute the test statistic.b. At 95% confidence using the p-value approach, test to see if taking the course actually increasedscores on the driving exam.

Q: Two independent samples are drawn from two populations, and the following information is provided.Population 1Population 2n34525565s1418We want to test the following hypotheses.Ho: 1-20Ha: 1-2< 0a. Determine the degrees of freedom.b. Compute the test statistic.c. At 95% confidence, test the hypotheses. Assume the two populations are normally distributed and have equal variances.

Q: Independent random samples taken at two companies provided the following information regarding annual salaries of the employees.Marissa, IncJason, Inc.Sample Size7250Sample Mean (in $1,000)4843Sample Standard Deviation (in $1,000)1210a. We want to determine whether or not there is a significant difference between the average salaries of the employees at the two companies. Compute the test statistic.b. Compute the p-value; and at 95% confidence, test the hypotheses.

Q: A recent Time magazine reported the following information about a sample of workers in Germany and the United States.United StatesGermanyAverage length of workweek (hours)4238Sample Standard Deviation56Sample Size600700We want to determine whether or not there is a significant difference between the average workweek in the United States and the average workweek in Germany.a. State the null and the alternative hypotheses.b. Compute the test statistic.c. Compute the p-value. What is your conclusion?

Q: Zip, Inc. manufactures Zip drives on two different manufacturing processes. Because the management of this company is interested in determining if process 1 takes less manufacturing time, they selected independent samples from each process. The results of the samples are shown below.Process 1Process 2Sample Size2722Sample Mean (in minutes)1014Sample Variance1625a. State the null and alternative hypotheses.b. Determine the degrees of freedom for thet test.c. Compute the test statisticd. At 95% confidence, test to determine if there is sufficient evidence to indicate that process 1 takes a significantly shorter time to manufacture the Zip drives.

Q: The Dean of Students at UTC has said that the average grade of UTC students is higher than that of the students at GSU. Random samples of grades from the two schools are selected, and the results are shown below.UTCGSUSample Size1412Sample Mean2.852.61Sample Standard Deviation0.400.35Sample Mode2.53.0a. Give the hypotheses.b. Compute the test statistic.c. At a 0.1 level of significance, test the Dean of Students' statement.

Q: Independent random samples taken at two local malls provided the following information regarding purchases by patrons of the two malls.Hamilton PlaceEastgateSample Size8593Average Purchase$143$150Standard Deviation$22$18We want to determine whether or not there is a significant difference between the average purchases by the patrons of the two malls.a. Give the hypotheses for the above.b. Compute the test statistic.c. At 95% confidence, test the hypotheses.

Q: Independent random samples of managers' yearly salaries (in $1000) taken from governmental and private organizations provided the following information. At 95% confidence, test to determine if there is a significant difference between the average salaries of the managers in the two sectors.GovernmentPrivate8075s910n2831

Q: Recently, a local newspaper reported that part time students are older than full time students. In order to test the validity of its statement, two independent samples of students were selected.Full TimePart Time2624s23n4231a. Give the hypotheses for the above.b. Determine the degrees of freedom.c. Compute the test statistic.d. At 95% confidence, test to determine whether or not the average age of part time students is significantly more thanfull time students.

Q: Consider the following hypothesis test:H0: 1-20Ha: 1-2> 0The following results are for two independent samples taken from two populations.Sample 1Sample 2Sample Size3534Sample Mean4337Sample Variance140170a. Determine the degrees of freedom for the tdistribution.b. Compute the test statistic.c. Determine the p-value and test the above hypotheses.

Q: A random sample of 89 tourists in the Grand Bahamas showed that they spent an average of $2,860 (in a week) with a standard deviation of $126; and a sample of 64 tourists in New Province showed that they spent an average of $2,935 (in a week) with a standard deviation of $138. We are interested in determining if there is any significant difference between the average expenditures of those who visited the two islands?a. Determine the degrees of freedom for this test.b. Compute the test statistic.c. Compute the p-value.d. What is your conclusion? Let = .05.

Q: The following information regarding the number of semester hours taken from random samples of day and evening students is provided.DayEvening1612s42n140160Develop a 95% confidence interval estimate for the difference between the mean semester hours taken by the two groups of students.

Q: The following information regarding the ages of full-time and part-time students are given. Using the following data, develop an interval estimate for the difference between the mean ages of the two populations. Use a 5% level of significance. The degrees of freedom for the tdistribution are 106.Full-TimePart-Time2724s1.52n5060

Q: In order to estimate the difference between the average yearly salaries of top managers in private and governmental organizations, the following information was gathered.PrivateGovernmentalSample Size5060Sample Mean (in $1,000s)190180Sample Standard Deviation (in $1,000s)68Develop an interval estimate for the difference between the average salaries of the two sectors. Let = .05.

Q: In order to estimate the difference between the average age of male and female employees at the Young Corporation, the following information was gathered. Male Female Sample Size 32 36 Sample Mean 25 23 Sample Standard Deviation 4 6 Develop a 95% confidence interval estimate for the difference between the average age of male and female employees at the Young Corporation.

Q: Test scores on a standardized test from samples of students from two universities are given below. UA UB Sample Size 28 41 Average Test Score 84 82 Variance 64 100 Provide a 98% confidence interval estimate for the difference between the test scores of the two universities.

Q: Samples of employees of Companies A and B provided the following information regarding the ages of employees.Company ACompany BSample Size3236Average Age4247Variance1636Develop a 97% confidence interval for the difference between the average ages of the employees of the two companies.

Q: Two independent random samples of annual starting salaries for individuals with masters and bachelors degrees in business were taken and the results are shown below.Masters DegreeBachelors DegreeSample Size3330Sample Mean (in $1,000)5854Sample Standard Deviation (in $1,000)2.42.0a. What are the degrees of freedom for the tdistribution?b. Provide a 95% confidence interval estimate for the difference between the salaries of the two groups.

Q: A credit company has gathered information regarding the average amount owed by people under 30 years old and by people over 30 years. Independent random samples were taken from both age groups. You are given the following information.Under 30Over 30600550n2003002361400Construct a 95% confidence interval for the difference between the average amounts owed by the two age groups.

Q: In order to estimate the difference between the average mortgages in the southern states and the northern states, the following information was gathered.SouthernNorthernSample Size4045Sample Mean (in $1,000)$170$175Sample Standard Deviation (in $1,000)$5$7a. Compute the degrees of freedom for the tdistribution.b. Develop an interval estimate for the difference between the average of the mortgages in the South and North. Let alpha = 0.05.

Q: The following are the test scores of two samples of students from University A and University B on a national statistics examination. Develop a 95% confidence interval estimate for the difference between the mean scores of the two populations.University A ScoresUniversity B Scores8683n648768

Q: Consider the following results for two samples randomly taken from two populations.Sample ASample BSample Size2830Sample Mean2422Sample Standard Deviation86a. Determine the degrees of freedom for the tdistribution.b. Develop a 95% confidence interval for the difference between the two population means.c. Is there conclusive evidence that one population has a larger mean? Explain.

Q: Consider the following results for two samples randomly taken from two populations.Sample ASample BSample Size2025Sample Mean2822Sample Standard Deviation56a. Determine the degrees of freedom for the tdistribution.b. At 95% confidence, what is the margin of error?c. Develop a 95% confidence interval for the difference between the two population means.

Q: Consider the following results for two samples randomly taken from two populations.Sample ASample BSample Size2538Sample Mean6660Sample Standard Deviation57a. What are the degrees of freedom for the tdistribution?b. At 95% confidence, compute the margin of error.c. Develop a 95% confidence interval for the difference between the two population means.

Q: Consider the following results for two samples randomly taken from two populations.Sample ASample BSample Size3135Sample Mean106102Sample Standard Deviation87a. Determine the degrees of freedom for the tdistribution.b. Develop a 95% confidence interval for the difference between the two population means.

Q: In order to estimate the difference between the average Miles per Gallon of two different models of automobiles, samples are taken and the following information is collected.Model AModel BSample Size6055Sample Mean2825Sample Variance169a. At 95% confidence develop an interval estimate for the difference between the average Miles per Gallon for the two models.b. Is there conclusive evidence to indicate that one model gets a higher MPG than the other? Why or why not?Explain.

Q: The management of Recover Fast Hospital (RFH) claims that the average length of stay in their hospital after a major surgery is less than the average length of stay at General Hospital (GH). The following data have been accumulated to test their claim.RFHGHSample size4558Mean (in days)4.64.9Population Standard Deviation ()0.50.6a. Formulate the hypotheses.b. Compute the test statistic.c. Using the p-value approach, test to see if the average length of stay in RFH is significantly less than the average length of stay in GH. Let = 0.05.