STATS 20 Multiple Choice Questions Set Solution

Question 1
According to the central limit theorem, if a sample of size 64 is drawn from a population with a mean of 56, the mean of all sample means would equal _________ .


7.00
56.00
64.00
0.875
128.00

Question 2
According to the central limit theorem, if a sample of size 100 is drawn from a population with a standard deviation of 80, the standard deviation of sample means would equal __________ .

0.80
8
80
800
0.080

Question 3
According to the central limit theorem, for samples of size 64 drawn from a population with ? = 800 and ? = 56, the standard deviation of the sampling distribution of sample means would equal __________ .

7
8
100
800
80


Question 4
Suppose a population has a mean of 90 and a standard deviation of 28. If a random sample of size 49 is drawn from the population, the probability of drawing a sample with a mean of more than 95 is _________ .


0.1056
0.3944
0.4286
0.8944
1.0000

Question 5
Suppose a population has a mean of 90 and a standard deviation of 28. If a random sample of size 49 is drawn from the population, the probability of drawing a sample with a mean between 85 and 95 is _________ .


0.1056
0.3944
0.7888
0.2112
0.5000

Question 6
Suppose a population has a mean of 90 and a standard deviation of 28. If a random sample of size 49 is drawn from the population, the probability of drawing a sample with a mean between 80 and 100 is _________ .


0.9876
0.0124
0.4938
0.0062
1.0000

Question 7
Suppose a population has a mean of 400 and a standard deviation of 24. If a random sample of size 144 is drawn from the population, the probability of drawing a sample with a mean of more than 404.5 is __________ .


0.0139
0.4861
0.4878
0.0122
0.5000

Question 8
Albert Abbasi, VP of Operations at Ingleside International Bank, is evaluating the service level provided to walk-in customers. Accordingly, he plans a sample of waiting times for walk-in customers. If the population of waiting times has a mean of 15 minutes and a standard deviation of 4 minutes, the probability that Albert's sample of 64 will have a mean less than 14 minutes is _________ .


0.4772
0.0228
0.9772
0.9544
1.0000

Question 9
Albert Abbasi, VP of Operations at Ingleside International Bank, is evaluating the service level provided to walk-in customers. Accordingly, he plans a sample of waiting times for walk-in customers. If the population of waiting times has a mean of 15 minutes and a standard deviation of 4 minutes, the probability that Albert's sample of 64 will have a mean between 13.5 and 16.5 minutes is __________ .


0.9974
0.4987
0.9772
0.4772
0.5000

Question 10
Suppose 40% of the population possess a given characteristic. If a random sample of size 300 is drawn from the population, then the probability that 44% or fewer of the samples possess the characteristic is __________ .


0.0793
0.4207
0.9207
0.9900
1.0000

Question 11
Suppose 30% of a population possess a given characteristic. If a random sample of size 1200 is drawn from the population, then the probability that less than 348 possess that characteristic is __________ .


0.2236
0.2764
0.2900
0.7764
0.3336

Question 12
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?

0.1064
0.2700
0.3936
0.6064
0.9000

Question 13
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?


0.4793
0.9793
0.0207
0.5207
0.6754

Question 14
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 ___________ .


0.4706
0.9706
0.0588
0.9412
0.8765



Question 15
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 __________ .


0.9232
0.0768
0.4616
0.0384
0.8976

Question 16
Kristen Ashford purchased the subscribers list for Wind Surfing magazine. She plans to survey a sample of the subscribers before using the list in her mail order business. She randomly selects the fourth name as a starting point and then selects every 50th subsequent name (54, 104, 154, etc.). Her sample is a ___________ .


simple random sample
stratified sample
systematic sample
convenience sample
cluster sample



Question 17
Pinky Bauer, Chief Financial Officer of Harrison Haulers, Inc., suspects irregularities in the payroll system. She knows that 2,500 payroll vouchers have been issued since January 1, 2000, and her staff doesn't have time to inspect each voucher. So, she randomly selects 53 as a starting point and orders her staff to inspect the 53rd voucher and each voucher at an increment of 100 (53, 153, 253, etc.). Her sample is a ____________ .


stratified sample
simple random sample
convenience sample
cluster sample
systematic sample

Question 18
Financial analyst Larry Potts needs a sample of 100 securities listed on the New York Stock Exchange. In the current issue of the Wall Street Journal, 2,531 securities are listed in the "New York Exchange Composite Transactions," an alphabetical listing of all securities traded on the previous business day. Larry uses a table of random numbers to select 100 numbers between 1 and 2,531. His sample is a ____________ .


quota sample
simple random sample
systematic sample
stratified sample
cluster sample



Question 19
On Saturdays, cars arrive at David Zebda's Scrub and Shine Car Wash at the rate of 80 cars per hour during the ten-hour shift. David wants a sample of 40 Saturday customers to answer the long version of his quality service questionnaire. He instructs the Saturday crew to select the first 40 customers. His sample is a __________ .


convenience sample
simple random sample
systematic sample
stratified sample
cluster sample





Question 20
A carload of palletized aluminum castings has arrived at Mansfield Motor Manufacturers. The car contains 1,000 pallets of 100 castings each. Mario Munoz, manager of Quality Assurance, directs the receiving crew to deliver the 127th and 869th pallets to his crew for 100% inspection. Mario randomly selected 127 and 869 from a table of random numbers. Mario's sample of 200 castings is a ____________ .


simple random sample
systematic sample
stratified sample
cluster sample
convenience sample