Q&A Hero

Q: Excel's __________ function can be used to compute the sample variance. a. MAX b. MODE c. VAR d. STDEV

Q: The numerical value of the standard deviation can never be a. larger than the variance b. zero c. negative d. all of these statements are correct

Q: The standard deviation of a sample of 100 observations equals 64. The variance of the sample equals a. 8 b. 10 c. 6,400 d. 4,096

Q: The variance of a sample of 81 observations equals 64. The standard deviation of the sample equals a. 0 b. 4096 c. 8 d. 6,561

Q: During a cold winter, the temperature stayed below zero for ten days (ranging from -20 to -5). The variance of the temperatures of the ten day period a. is negative since all the numbers are negative b. must be at least zero c. can not be computed since all the numbers are negative d. can be either negative or positive

Q: If the variance of a data set is correctly computed with the formula using n1 in the denominator, which of the following is true? a. the data set is a sample b. the data set is a population c. the data set could be either a sample or a population d. the data set is from a census

Q: The value of the sum of the squared deviations from the mean, i.e., must always be a. less than the mean b. negative c. either positive or negative depending on whether the mean is negative or positive d. at least zero

Q: The sum of deviations of the individual data elements from their mean is a. always greater than zero b. always less than zero c. sometimes greater than and sometimes less than zero, depending on the data elements d. always equal to zero

Q: The population variance can never be a. zero b. larger than the standard deviation c. negative d. all of these are correct

Q: The variance of the sample a. can never be negative b. can be negative c. cannot be zero d. cannot be less than one

Q: The sample variance a. is always smaller than the true value of the population variance b. is always larger than the true value of the population variance c. could be smaller, equal to, or larger than the true value of the population variance d. can never be zero

Q: The interquartile range is used as a measure of variability to overcome what difficulty of the range? a. the sum of the range variances is zero b. the range is difficult to compute c. the range is influenced too much by extreme values d. the range is negative

Q: The interquartile range is a. the 50thpercentile b. another name for the variance c. the difference between the largest and smallest values d. the difference between the third quartile and the first quartile

Q: The difference between the largest and the smallest data values is the a. variance b. interquartile range c. range d. coefficient of variation

Q: Refer to Exhibit 3-1. The 75thpercentile is a. 5 b. 6 c. 7 d. 8

Q: Refer to Exhibit 3-1. The mean is a. 5 b. 6 c. 7 d. 8

Q: Refer to Exhibit 3-1. The mode is a. 5 b. 6 c. 7 d. 8

Q: Exhibit 3-1A researcher has collected the following sample data.512685675124Refer to Exhibit 3-1. The median isa. 5b. 6c. 7d. 8

Q: The measure of location that is the most likely to be influenced by extreme values in the data set is thea. rangeb. medianc. moded. mean

Q: The median of a sample will always equal the a. mode b. mean c. 50thpercentile d. all of these answers are correct

Q: Which of the following is nota measure of location? a. mean b. median c. variance d. mode

Q: The first quartile a. contains at least one third of the data elements b. is the same as the 25thpercentile c. is the same as the 50thpercentile d. is the same as the 75thpercentile

Q: The 75thpercentile is also the a. first quartile b. second quartile c. third quartile d. fourth quartile

Q: The 50thpercentile is the a. mode b. median c. mean d. third quartile

Q: In computing the pthpercentile, if the index i is an integer the pthpercentile is thea. average of data values in position i-1 and ib. data value in position ic. data value in position i + 1d. average of data values in position iand i + 1

Q: Excel provides functions for computing the a. mean b. median c. mode d. Excel provides functions for all of these.

Q: Excel's __________ function can be used to compute the mode. a. MAX b. AVERAGE c. MEDIAN d. MODE

Q: Excel's __________ function can be used to compute the median. a. MAX b. AVERAGE c. MEDIAN d. MODE

Q: Excel's __________ function can be used to compute the mean. a. MAX b. AVERAGE c. MEDIAN d. MODE

Q: Since the mode is the most frequently occurring data value, it a. can never be larger than the mean b. is always larger than the median c. is always larger than the mean d. None of the other answers are correct.

Q: The most frequently occurring value of a data set is called the a. range b. mode c. mean d. None of the other answers are correct.

Q: Since the median is the middle value of a data set, it must always be a. smaller than the mode b. larger than the mode c. smaller than the mean d. None of the other answers are correct.

Q: If a data set has an even number of observations, the median a. can not be determined b. is the average value of the two middle items c. must be equal to the mean d. is the average value of the two middle items when all items are arranged in ascending order

Q: After the data has been arranged from smallest value to largest value, the value in the middle is called the a. range b. median c. mean d. None of the other answers are correct.

Q: Since the population is always larger than the sample, the value of the sample mean a. is always smaller than the true value of the population mean b. is always larger than the true value of the population mean c. is always equal to the true value of the population mean d. could be larger, equal to, or smaller than the true value of the population mean

Q: The mean of the sample a. is always larger than the mean of the population from which the sample was taken b. is always smaller than the mean of the population from which the sample was taken c. can never be zero d. None of the other answers are correct.

Q: The mean of a sample is a. always equal to the mean of the population b. always smaller than the mean of the population c. computed by summing the data values and dividing the sum by (n1) d. computed by summing all the data values and dividing the sum by the number of items

Q: is an example of aa. population parameterb. sample statisticc. population varianced. mode

Q: Since the population size is always larger than the sample size, then the sample statistic a. can never be larger than the population parameter b. can never be equal to the population parameter c. can never be zero d. None of the other answers are correct.

Q: A numerical measure, such as a mean, computed from a population is known as a a. population parameter b. sample parameter c. sample statistic d. sample mean

Q: A numerical measure computed from a sample, such as sample mean, is known as a a. population parameter b. sample parameter c. sample statistic d. population mean

Q: Which of the following descriptive statistics is not measured in the same units as the data? a. 35thpercentile b. standard deviation c. variance d. interquartile range

Q: The coefficient of variation indicates how large the standard deviation is relative to the a. mean b. median c. range d. variance

Q: A box plot is a graphical representation of data that is based on a. the empirical rule b. z-scores c. a histogram d. a five-number summary

Q: The empirical rule states that, for data having a bell-shaped distribution, the percentage of data values being within one standard deviation of the mean is approximately a. 34 b. 50 c. 68 d. 95

Q: Which of the following is not a measure of variability of a single variable? a. range b. covariance c. standard deviation d. coefficient of variation

Q: In computing descriptive statistics for grouped data, the ____ are used to approximate the data values in each class. a. class lower limits b. class upper limits c. class midpoints d. class ranges

Q: The measure of variability easiest to compute, but seldom used as the only measure, is the a. range b. interquartile range c. standard deviation d. variance

Q: An important measure of location for qualitative data is the a. mean b. median c. mode d. margin

Q: Generally, which one of the following is the least appropriate measure of central tendency for a data set that contains outliers? a. mean b. median c. 2ndquartile d. 50thpercentile

Q: The coefficient of determination is equal to the a. absolute value of the correlation coefficient b. squared value of the correlation coefficient c. square-root of the correlation coefficient d. inverse value of the correlation coefficient

Q: The interquartile range is the difference between the a. first and second quartiles b. first and third quartiles c. second and third quartiles d. second and fourth quartiles

Q: Ron Butler, a custom home builder, is looking over the expenses he incurred for a house he just completed constructing. For the purpose of pricing future construction projects, he would like to know the average wage ($/hour) he paid the workers he employed. Listed below are the categories of worker he employed, along with their respective wage and total hours worked. What is the average wage ($/hour) he paid the workers?WorkerWage ($/hr)Total HoursCarpenter21.60520Electrician28.72230Laborer11.80410Painter19.75270Plumber24.16160

Q: Missy Walters owns a mail-order business specializing in baby clothes. She is considering offering her customers a discount on shipping charges based on the dollar-amount of the mail order. Before Missy decides the discount policy, she needs a better understanding of the dollar-amount distribution of the mail orders she receives. Missy had an assistant randomly select 50 recent orders and record the value, to the nearest dollar, of each order as shown below.136281226123178445231389196175211162212241182290434167246338194242368258323196183209198212277348173409264237490222472248231154166214311141159362189260a. Determine the mean, median, and mode for this data set.b. Determine the 80thpercentile.c. Determine the first quartile.d. Determine the range and interquartile range.e. Determine the sample variance, sample standard deviation, and coefficient of variation.f. Determine the z-scores for the minimum and maximum values in the data set.

Q: Del Michaels had a successful morning, or so he thinks, selling 1300 surplus notebook computers over the telephone to three commercial customers. The three customers were not equally skillful at negotiating a low unit price. Customer A bought 600 computers for $1252 each, B bought 300 units at $1310 each, and C bought 400 at $1375 each.a. What is the average unit price at which Del sold the 1300 computers?b. Del's manager told Del he expected him to sell, by the end of the day, a total of 2500 surplus computers at an average price of $1312 each. What is the average unit price at which Del must sell the remaining 1200 computers?

Q: The following is a frequency distribution for the ages of a sample of employees at a local company.AgeFrequency30 - 39240 - 49350 - 59760 - 69570 - 791a. Determine the average age for the sample.b. Compute the variance.c. Compute the standard deviation.d. Compute the coefficient of variation.

Q: A sample of charge accounts at a local drug store revealed the following frequency distribution of unpaid balances.Unpaid Balance ($)Frequency10 - 29530 - 491050 - 69670 - 89990 - 10920a. Determine the mean unpaid balance.b. Determine the standard deviation.c. Compute the coefficient of variation.

Q: The following frequency distribution shows the time (in minutes) that a sample of students uses the computer terminals per day.Time (minutes)Frequency20 - 39240 - 59460 - 79680 - 994100 - 1192a. Compute the mean.b. Compute the variance.c. Compute the standard deviation.d. Compute the coefficient of variation.

Q: The starting salaries of a sample of college students are given below.Starting Salary ($1000s)Frequency10 - 14215 - 19320 - 24525 - 29730 - 34235 - 391a. Compute the mean.b. Compute the variance.c. Compute the standard deviation.d. Compute the coefficient of variation.

Q: The following is a frequency distribution of grades for a statistics examination.Examination GradeFrequency40 - 49350 - 59560 - 691170 - 792280 - 891590 - 996Treating these data as a sample, compute the following:a. The meanb. The standard deviationc. The varianced. The coefficient of variation

Q: The following frequency distribution shows the ACT scores of a sample of students:ScoreFrequency14 - 18219 - 23524 - 281229 - 331For the above data, compute the following.a. The meanb. The standard deviation

Q: Consider the data in the following frequency distribution. Assume the data represent a population.ClassFrequency2- 627 - 11312 - 16417 - 211For the above data, compute the following.a. The meanb. The variancec. The standard deviation

Q: Paul, a freshman at a local college just completed 15 credit hours. His grade report is presented below. Course Credit Hours Grades Calculus 5 C Biology 4 A English 3 D Music 2 B P.E. 1 A The local university uses a 4 point grading system, i.e., A = 4, B = 3, C = 2, D = 1, F = 0. Compute Paul's semester grade point average.

Q: Compute the weighted mean for the following data.XiWeight (wi)19121730142813101810

Q: Compute the weighted mean for the following data.xiWeight (wi)910812543523

Q: The following data represent the daily demand (yin thousands of units) and the unit price (xin dollars) for a product.Daily Demand (y)Unit Price (x)4713933554433462081516306a. Compute and interpret the sample covariance for the above data.b. Compute and interpret the sample correlation coefficient.

Q: The following observations are given for two variables.Yx5281218320622113019101879a. Compute and interpret the sample covariance for the above data.b. Compute and interpret the sample correlation coefficient.

Q: Provide a five-number summary for the follow data.115191153194236184216185183202

Q: Suppose annual salaries for sales associates from a particular store have a mean of $32,500 and a standard deviation of $2,500.a. Calculate and interpret the z-score for a sales associate who makes $36,000.b. Use Chebyshev's theorem to calculate the percentage of sales associates with salaries between $26,250 and $38,750.c. Suppose that the distribution of annual salaries for sales associates at this store is bell-shaped. Use the empirical rule to calculate the percentage of sales associates with salaries between $27,500 and $37,500.d. Use the empirical rule to determine the percentage of sales associates with salaries less than $27,500.e. Still suppose that the distribution of annual salaries for sales associates at this store is bell-shaped. A sales associate makes $42,000. Should this salary be considered an outlier? Explain.

Q: A sample of 11 individuals shows the following monthly incomes.IndividualIncome ($)11,50022,00032,50044,00054,00062,50072,00084,00093,500103,0001143,000a. What would be a representative measure of central location for the above data? Explain.b. Determine the mode.c. Determine the median.d. Determine the 60thpercentile.e. Drop the income of individual number 11 and compute the standard deviation for the first 10 individuals.

Q: A sample of 9 mothers was taken. The mothers were asked the age of their oldest child. You are given their responses below.312471462911a. Compute the mean.b. Compute the variance.c. Compute the standard deviation.d. Compute the coefficient of variation.e. Determine the 25th percentile.f. Determine the mediang. Determine the 75th percentile.h. Determine the range.

Q: A sample of twelve families was taken. Each family was asked how many times per week they dine in restaurants. Their responses are given below.210202120212Using this data set, compute thea. modeb. medianc. meand. rangee. interquartile rangef. varianceg. standard deviationh. coefficient of variation

Q: A researcher has obtained the number of hours worked per week during the summer for a sample of fifteen students.40253530204030204010302010520Using this data set, compute thea. medianb. meanc. moded. 40th percentilee. rangef. sample varianceg. standard deviation

Q: The number of hours worked per week for a sample of ten students is shown below.StudentHours1202031841652264078869301040a. Determine the median and explain its meaning.b. Compute the 70th percentile and explain its meaning.c. What is the mode of the above data? What does it signify?

Q: The amount of time that a sample of students spends watching television per day is given below.StudentTime (minutes)140228371448549635740857a. Compute the mean.b. Compute the median.c. Compute the standard deviation.d. Compute the 75th percentile.

Q: The following data show the yearly salaries of football coaches at some state-supported universities.UniversitySalary ($1,000)A53B44C68D47E62F59G53H94For the above sample, determine the following measures.a. The mean yearly salaryb. The standard deviationc. The moded. The mediane. The 70th percentile

Q: A private research organization studying families in various countries reported the following data for the amount of time 4-year old children spent alone with their fathers each day.CountryTime with Dad (minutes)Belgium30Canada44China54Finland50Germany36Nigeria42Sweden46United States42For the above sample, determine the following measures:a. The meanb. The standard deviationc. The moded. The 75th percentile

Q: For the following data201817232219211723Compute the following measures:a. The meanb. The variancec. The standard deviationd. The coefficient of variatione. The 25th percentilef. The mediang. The 75th percentile

Q: For the following data579111519Compute the following measures:a. The meanb. The variancec. The standard deviationd. The coefficient of variatione. The 25thpercentilef. The mediang. The 75thpercentile

Q: In 1998, the average age of students at UTC was 22 with a standard deviation of 3.96. In 1999, the average age was 24 with a standard deviation of 4.08. In which year do the ages show a more dispersed distribution? Show your complete work and support your answer.