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Q:
A random sample of 64 items is selected from a population of 400 items. The sample mean is 200. The population standard deviation is 48. From this data, a 90% confidence interval to estimate the population mean can be computed as _______.
a) 189.21 to 210.79
b) 188.24 to 211.76
c) 190.13 to 209.87
d) 190.94 to 209.06
e) 193.45 to 211.09
Q:
A random sample of 64 items is selected from a population of 400 items. The sample mean is 200. The population standard deviation is 48. From this data, a 95% confidence interval to estimate the population mean can be computed as _______.
a) 189.21 to 210.79
b) 188.24 to 211.76
c) 190.13 to 209.87
d) 190.94 to 209.06
e) 193.45 to 211.09
Q:
James Desreumaux, VP of Human Resources of American First Banks (AFB), is reviewing the employee training programs of AFB banks. His staff randomly selected personnel files for 100 tellers in the Southeast Region and determined that their mean training time was 25 hours. Assume that the population standard deviation is 5 hours. The 95% confidence interval for the population mean of training times is ________.
a) 15.20 to 34.80
b) 24.18 to 25.82
c) 24.02 to 25.98
d) 16.78 to 33.23
e) 23.32 to 35.46
Q:
James Desreumaux, VP of Human Resources of American First Banks (AFB), is reviewing the employee training programs of AFB banks. His staff randomly selected personnel files for 100 tellers in the Southeast Region and determined that their mean training time was 25 hours. Assume that the population standard deviation is 5 hours. The 92% confidence interval for the population mean of training times is ________.
a) 16.25 to 33.75
b) 24.30 to 25.71
c) 17.95 to 32.05
d) 24.12 to 25.88
e) 24.45 to 27.32
Q:
James Desreumaux, VP of Human Resources of American First Banks (AFB), is reviewing the employee training programs of AFB banks. His staff randomly selected personnel files for 100 tellers in the Southeast Region and determined that their mean training time was 25 hours. Assume that the population standard deviation is 5 hours. The 88% confidence interval for the population mean of training times is ________.
a) 17.25 to 32.75
b) 24.23 to 25.78
c) 24.42 to 25.59
d) 19.15 to 30.85
e) 21.00 t0 32.00
Q:
Brian Vanecek, VP of Operations at Portland Trust Bank, is evaluating the service level provided to walk-in customers. Accordingly, his staff recorded the waiting times for 64 randomly selected walk-in customers and determined that their mean waiting time was 15 minutes. Assume that the population standard deviation is 4 minutes. The 95% confidence interval for the population mean of waiting times is ________.
a) 14.02 to 15.98
b) 7.16 to 22.84
c) 14.06 to 15.94
d) 8.42 to 21.58
e) 19.80 to 23.65
Q:
Brian Vanecek, VP of Operations at Portland Trust Bank, is evaluating the service level provided to walk-in customers. Accordingly, his staff recorded the waiting times for 64 randomly selected walk-in customers and determined that their mean waiting time was 15 minutes. Assume that the population standard deviation is 4 minutes. The 90% confidence interval for the population mean of waiting times is ________.
a) 14.27 to 15.73
b) 14.18 to 15.82
c) 9.88 to 20.12
d) 13.86 to 16.14
e) 18.12 to 19.87
Q:
Suppose a researcher is interested in understanding the variation in the price of store brand milk. A random sample of 36 grocery stores selected from a population and the mean price of store brand milk is calculated. The sample mean is $3.13 with a standard deviation of $0.23. Construct a 95% confidence interval to estimate the population mean.
a) $3.03 to $3.23
b) $3.12 to $3.14
c) $3.05 to $3.21
d) $2.90 to $3.36
e) $3.06 to $3.20
Q:
Suppose a researcher is interested in understanding the variation in the price of store brand milk. A random sample of 36 grocery stores selected from a population and the mean price of store brand milk is calculated. The sample mean is $3.13 with a standard deviation of $0.23. Construct a 92% confidence interval to estimate the population mean..
a) $3.03 to $3.23
b) $3.12 to $3.14
c) $3.05 to $3.21
d) $2.90 to $3.36
e) $3.06 to $3.20
Q:
Suppose a researcher is interested in understanding the variation in the price of store brand milk. A random sample of 36 grocery stores selected from a population and the mean price of store brand milk is calculated. The sample mean is $3.13 with a standard deviation of $0.23. Construct a 99% confidence interval to estimate the population mean..
a) $3.03 to $3.23
b) $3.12 to $3.14
c) $3.05 to $3.21
d) $2.90 to $3.36
e) $3.06 to $3.20
Q:
The z value associated with a two"‘sided 88% confidence interval is _______.
a) 1.28
b) 1.55
c) 1.17
d) 0.88
e) 1.90
Q:
The z value associated with a two"‘sided 80% confidence interval is _______.
a) 1.645
b) 1.28
c) 0.84
d) 0.29
e) 2.00
Q:
The z value associated with a two"‘sided 95% confidence interval is _______.
a) 1.28
b) 1.645
c) 1.96
d) 2.575
e) 2.33
Q:
The z value associated with a two"‘sided 90% confidence interval is _______.
a) 1.28
b) 1.645
c) 1.96
d) 2.575
e) 2.33
Q:
Eugene Gates, Marketing Director of Mansfield Motors Manufacturers, Inc.'s Electrical Division, is leading a study to assess the relative importance of product features. An item on a survey questionnaire distributed to 100 of Mansfield's customers asked them to rate the importance of "ease of maintenance" on a scale of 1 to 10 (with 1 meaning "not important" and 10 meaning "highly important"). His staff assembled the following statistics. Ease of Maintenance Mean
7.5 Standard Deviation
1.5 If Eugene concludes that the average rate of "ease of maintenance" for all customers is 7.5, he is using ________.
a) a range estimate
b) a statistical parameter
c) a point estimate
d) an interval estimate
e) a guesstimate
Q:
Brian Vanecek, VP of Operations at Portland Trust Bank, is evaluating the service level provided to walk-in customers. Accordingly, his staff recorded the waiting times for 45 randomly selected walk-in customers, and calculated that their mean waiting time was 15 minutes. If Brian concludes that the average waiting time for all walk-in customers is 15 minutes, he is using a ________.
a) a range estimate
b) a statistical parameter
c) an interval estimate
d) a point estimate
e) an exact estimate
Q:
Catherine Chao, Director of Marketing Research, is evaluating consumer acceptance of a new toothpaste package. Her staff reports that 17% of a random sample of 200 households prefers the new package to all other package designs. If Catherine concludes that 17% of all households prefer the new package, she is using _______.
a) a point estimate
b) a range estimate
c) a statistical parameter
d) an interval estimate
e) an exact estimate
Q:
Given the error we are willing to tolerate, the sample size is determined by the mean of the population and the confidence level.
Q:
In estimating the sample size necessary to estimate a population mean, the error of estimation, E, is equal to the difference between the sample mean and the sample standard deviation.
Q:
Like a t-distribution, a chi-square distribution is symmetrical and extends from minus infinity to plus infinity.
Q:
Use of the chi-square statistic to estimate the population variance is extremely robust to the assumption that the population is normally distributed.
Q:
In determining the interval estimates for a population variance using the sample variance, it is appropriate to use the values from a chi-square distribution rather than a t-distribution.
Q:
A market researcher computed a confidence interval for a population proportion using a 95% confidence level. Her boss decided that she wanted a 99% confidence level instead. The new interval with 99% confidence level will be widerthan the original one with a 95% confidence level.
Q:
In determining the interval estimates for a population proportion using the sample proportion, it is appropriate to use the z-distribution.
Q:
If the degrees of freedom in a t distribution increase, difference between the t values and the z values will also increase.
Q:
In order to find values in the t distribution table, you must determine the appropriate degrees of freedom based on the sample sizes.
Q:
A t-distribution is similar to a normal distribution, but with flatter tails.
Q:
An assumption underlying the use of t-statistic in sample-based estimation is that the population is normally distributed.
Q:
When the population standard deviation, , is unknown the sample standard deviation, s, is used in determining the interval estimate for the population mean.
Q:
You are thinking of using a t-table to find a 95 percent confidence interval for the mean μ of a population. The distribution of the population is normal and the population standard deviation is unknown. A random sample of size n is drawn from this population. You may use the t-distribution only if the sample size n is small.
Q:
Suppose a random sample of 16 is selected from a population with a normal distribution with a known population standard deviation σ of 10. Assume that the sample mean is 4.2. Based on a 90% confidence interval for the population mean, we can conclude that 0.1 is a plausible number for the population mean μ.
Q:
If the population is normal and its standard deviation, , is known and the sample size, n, is large (n ≥ 30), interval estimates for the population mean must be determined using z-values.
Q:
If the population is normal and its standard deviation, , is known but the sample size is small, z-distribution values may not be used to determine interval estimates for the population mean.
Q:
If the population is not normal but its standard deviation, is known and the sample size, n is large (n ≥ 30), z-distribution values may be used to determine interval estimates for the population mean.
Q:
When a range of values is used to estimate a population parameter, it is called a range estimate.
Q:
When a statistic calculated from sample data is used to estimate a population parameter, it is called a point estimate.
Q:
Paige DeMarco is the Vice President for University Advancement at State University. She is responsible for the capital campaign to raise money for the new student services building. Paige plans to target alumni and acquires her sampling frame from the State University Office of Alumni Relations. She intends to contact these individuals regarding possible donations. Paige chooses her sample by selecting six-digit numbers (1 to 150,000) from a random number table. Her sample is a _________.a) simple random sampleb) stratified samplec) systematic sampled) convenience samplee) cluster sample
Q:
Paige DeMarco is the Vice President for University Advancement at State University. She is responsible for the capital campaign to raise money for the new student services building. Paige plans to target alumni and acquires her sampling frame from the State University Office of Alumni Relations. She intends to contact these individuals regarding possible donations. She randomly selects the sixth name as a starting point and then selects every 100th subsequent name (106, 206, 306, etc.). Her sample is a _________.
a) simple random sample
b) stratified sample
c) systematic sample
d) convenience sample
e) cluster sample
Q:
Paige DeMarco is the Vice President for University Advancement at State University. She is responsible for the capital campaign to raise money for the new student services building. Paige selects the first 100 alumni listed on a web-based social networking site for State University. She intends to contact these individuals regarding possible donations. Her sample is a _________.
a) simple random sample
b) stratified sample
c) systematic sample
d) convenience sample
e) cluster sample
Q:
Suppose 90% of students in some specific college have a computer at home and a sample of 40 students is taken. The probability that more than 30 of those in the sample have a computer at home can be approximated using the normal approximation.
Q:
The sampling distribution of has a mean equal to the square root of the populationproportion p.
Q:
The sampling distribution of is close to normal provided that n≥30.
Q:
The sampling distribution of the sample means is less variable than the population distribution.
Q:
The sampling distribution of the sample means is close to the normal distribution only if the distribution of the population is close to normal.
Q:
If the population is normally distributed, the sample means of size n=5 are normally
distributed.
Q:
The mean of the sample means is the same as the mean of the population
Q:
Increasing the sample size causes the numerical value of standard error of the sample means to increase.
Q:
The central limit theorem states that if the sample size, n, is large enough (n ≥20), the distribution of the sample means is normally distributed regardless of the shape of the population.
Q:
The standard deviation of a sampling distribution of the sample means is commonly called the standard error of the mean.
Q:
A sampling distribution is the distribution of a sample statistic such as the sample mean or sample proportion.
Q:
Sampling errors cannot by determined objectively for nonrandom sampling techniques.
Q:
A nonrandom sampling technique that is similar to stratified random sampling is called quota sampling.
Q:
If every unit of the population has the same probability of being selected to the sample, then the researcher is conducting random sampling.
Q:
If a researcher selects every kth item from a population of N items, then she is likely conducting a systematic random sampling.
Q:
With cluster sampling, there is homogeneity within a subgroup or stratum.
Q:
If every unit of the population has the same probability of being selected to the sample, then the researcher is probably conducting random sampling.
Q:
The two major categories of sampling methods are proportionate and disproportionate sampling.
Q:
The directory or map from which a sample is taken is called the census.
Q:
A major limitation of nonrandom samples is that they are not appropriate for most statistical methods.
Q:
Systematic sampling is a type of random sampling technique.
Q:
Cluster (or area) sampling is a type of random sampling technique.
Q:
In a random sampling technique, every unit of the population has a randomly varying chance or probability of being included in the sample.
Q:
A population list, map, directory, or other source used to represent the population from which a sample is taken is called a frame.
Q:
In some situations, sampling may be the only option because the population is inaccessible.
Q:
Saving time and money are reasons to take a sample rather than do a census.
Q:
Suppose 65% of all college students have a laptop computer at home and a sample of 150 is taken. The standard deviation of the sampling distribution of isa) 0.0015b) 0.0389c) 0.6500d) 0.4769e) 0.0477
Q:
Suppose 65% of all college students have a laptop computer at home and a sample of 150 students is taken. The mean of the sampling distribution of isa) 0.65b) 6.5c) 97.5d) 0.975e) 15.0
Q:
In an instant lottery, your chance of winning is 0.1. If you play the lottery 100 times and outcomes are independent, the probability that you win at least 15 percent of the time is
a) 0.4933
b) 0.5
c) .15
d) 0.0478
e) 0.9213
Q:
Catherine Chao, Director of Marketing Research, needs a sample of Kansas City households to participate in the testing of a new toothpaste package. If 40% of the households in Kansas City prefer the new package, the probability that Catherine's random sample of 300 households will have a sample proportion between 0.35 and 0.45 is ___________.
a) 0.9232
b) 0.0768
c) 0.4616
d) 0.0384
e) 0.8976
Q:
Catherine Chao, Director of Marketing Research, needs a sample of Kansas City households to participate in the testing of a new toothpaste package. If 40% of the households in Kansas City prefer the new package, the probability that Catherine's random sample of 300 households will have a sample proportion greater than 0.45 is ___________.
a) 0.9232
b) 0.0768
c) 0.4616
d) 0.0384
e) 0.8974
Q:
Pinky Bauer, Chief Financial Officer of Harrison Haulers, Inc., suspects irregularities in the payroll system. If 10% of the 5,000 payroll vouchers issued since January 1, 2000, have irregularities, the probability that Pinky's random sample of 200 vouchers will have a sample proportion of between .06 and .14 is ___________.
a) 0.4706
b) 0.9706
c) 0.0588
d) 0.9412
e) 0.8765
Q:
Pinky Bauer, Chief Financial Officer of Harrison Haulers, Inc., suspects irregularities in the payroll system. If 10% of the 5,000 payroll vouchers issued since January 1, 2000, have irregularities, the probability that Pinky's random sample of 200 vouchers will have a sample proportion greater than .06 is ___________.
a) 0.4706
b) 0.9706
c) 0.0588
d) 0.9412
e) 0.9876
Q:
Suppose 40% of all college students have a computer at home and a sample of 100 is taken. What is the probability that more than 50 of those in the sample have a computer at home?
a) 0.4793
b) 0.9793
c) 0.0207
d) 0.5207
e) 0.6754
Q:
Suppose 40% of all college students have a computer at home and a sample of 64 is taken. What is the probability that more than 30 of those in the sample have a computer at home?
a) 0.3686
b) 0.1314
c) 0.8686
d) 0.6314
e) 0.1343
Q:
If the population proportion is 0.90 and a sample of size 64 is taken, what is the probability that the sample proportion is more than 0.89?
a) 0.1064
b) 0.2700
c) 0.3936
d) 0.6064
e) 0.9000
Q:
If the population proportion is 0.90 and a sample of size 64 is taken, what is the probability that the sample proportion is less than 0.88?
a) 0.2019
b) 0.2981
c) 0.5300
d) 0.7019
e) 0.7899
Q:
Suppose 30% of the U.S. population has green eyes. If a random sample of size 1200 U.S. citizens is drawn, then the probability that less than 348 U.S. citizens have green eyes is _______.
a) 0.2236
b) 0.2764
c) 0.2900
d) 0.7764
e) 0.3336
Q:
Suppose 40% of the population of pre-teens have a TV in their bedroom. If a random sample of 500 pre-teens is drawn from the population, then the probability that between 36% and 44% of the pre-teens have a TV in their bedroom is _______.a) 0.9644b) 0.4644c) 0.0356d) 0.9328e) 0.0712
Q:
Suppose 40% of the population of pre-teens have a TV in their bedroom. If a random sample of 500 pre-teens is drawn from the population, then the probability that 44% or more of the pre-teens have a TV in their bedroom is _______.a) 0.9644b) 0.4644c) 0.0356d) 0.0400e) 0.9600
Q:
Suppose 40% of the population of pre-teens have a TV in their bedroom. If a random sample of 500 pre-teens is drawn from the population, then the probability that 44% or fewer of the pre-teens have a TV in their bedroom is _______.
a) 0.9644
b) 0.4644
c) 0.0356
d) 0.0400e) 0.9600