Deck 7: Sampling and Sampling Distributions

Question 1

The manager of the customer service division of a major consumer electronics company is interested in determining whether the customers who have purchased a DVD player made by the company over the past 12 months are satisfied with their products. Which of the following will be a good frame for drawing a sample?

A) telephone directory
B) voting registry
C) the list of customers who returned the registration card
D) a list of potential customers purchased from a database marketing company

Answer 1

C

Question 2

The evening host of a dinner dance reached into a bowl, mixed all the tickets around, and selected the ticket to award the grand door prize. What sampling method was used?

A) simple random sample
B) systematic sample
C) stratified sample
D) cluster sample

Answer 2

A

Question 3

To find out the potential impact of a new zoning law on a neighborhood, the legislators conduct a focus group interview by inviting the members of the housing owners association of that neighborhood. This is an example of a

A) systematic sample.
B) simple random sample.
C) judgment sample.
D) cluster sample.

Answer 3

C

Question 4

Which of the following sampling methods is a probability sample?

A) convenience sample
B) quota sample
C) stratified sample
D) judgment sample

Question 5

To obtain a sample of 10 books in the store, the manager walked to the first shelf next to the cash register to pick the first 10 books on that shelf. This is an example of a

A) systematic sample.
B) simple random sample.
C) stratified sample.
D) convenience sample.

Question 6

Which of the following yields a cluster sample?

A) All students in a class are divided into groups of 15. One student is randomly chosen from the first group, the remaining observations are every 15th student thereafter.
B) The best 15 students, according to the opinion of the instructor, in a class are selected.
C) All students in a class are grouped according to their gender. A random sample of 8 is selected from the males and a separate random sample of 7 is selected from the females.
D) All students in a class are divided into groups according to the rows in which they are seated. One of the groups is randomly selected.

Question 7

Which of the following yields a simple random sample?

A) All students in a class are divided into groups of 15. One student is randomly chosen from the first group, the remaining observations are every 15th student thereafter.
B) The best 15 students, according to the opinion of the instructor, in a class are selected.
C) The names of 50 students in a class are written on 50 different pieces of paper and put in a hat. The first 15 pieces of paper are selected blindly one at a time without replacing them back in the hat after shuffling the papers thoroughly.
D) All students in a class are divided into groups according to the rows in which they are seated. One of the groups is randomly selected.

Question 8

To gather information on the preferences of instructors at universities on topics for a business statistics textbook that it will publish, a publishing company invited 10 faculty members who have adopted one of the textbooks that it has published. This is an example of a

A) systematic sample.
B) judgment sample.
C) simple random sample.
D) stratified sample.

Question 9

To demonstrate a sampling method, the instructor in a class picked the first five students sitting in the last row of the class. This is an example of a

A) systematic sample.
B) simple random sample.
C) stratified sample.
D) convenience sample.

Question 10

For a population frame containing N = 1,007 individuals, what code number should you assign to the first person on the list in order to use a table of random numbers?

A) 0
B) 1
C) 01
D) 0001

Question 11

Which of the following scenarios will yield a nonprobability sample?

A) The subjects of the sample are chosen on the basis of known probability.
B) Items or individuals are chosen without regard to their probability of occurrence.
C) Every individual or item from the frame has an equal chance of being selected. Selection may be with replacement or without replacement.
D) Decide on a sample size, n; divide the frame of N individuals into groups of k individuals where k = N/n; randomly select one individual from the first group; select every kth individual thereafter.

Question 12

Which of the following yields a systematic sample?

A) All students in a class are divided into groups of 15. One student is randomly chosen from the first group, the remaining observations are every 15th student thereafter.
B) The best 15 students, according to the opinion of the instructor, in a class are selected.
C) All students in a class are grouped according to their gender. A random sample of 8 is selected from the males and a separate random sample of 7 is drawn from the females.
D) A random sample of 15 students is selected from a class without replacement.

Question 13

Which of the following is NOT a reason for selecting a sample?

A) A sample is less time consuming than a census.
B) A sample is less costly to administer than a census.
C) A sample is usually not a good representation of the target population.
D) A sample is less cumbersome and more practical to administer.

Question 14

At U.S. Data Corporation's web site, they advertised that "Because of our commitment to quality and our vast amount of industry knowledge and experience, we have grown to be one of America's leading providers of mailing lists, marketing data, sales leads and research data. We maintain databases of information on consumers and businesses nationwide that set industry standards for mission critical currency, reliability, and accuracy." Trying to reach 500 potential donors for their annual phone donation campaign, a local fire department purchased a list of donors from the company. This list is an example of a

A) population.
B) statistic.
C) parameter.
D) frame.

Question 15

Which of the following types of samples can you use if you want to make valid statistical inferences from a sample to a population?

A) a judgment sample
B) a quota sample
C) a convenience sample
D) a probability sample

Question 16

Which of the following is NOT a reason for the need for sampling?

A) It is usually too costly to study the whole population.
B) It is usually too time consuming to look at the whole population.
C) It is sometimes destructive to observe the entire population.
D) It is always more informative by investigating a sample than the entire population.

Question 17

Which of the following yields a stratified sample?

A) All students in a class are divided into groups of 15. One student is randomly chosen from the first group, the remaining observations are every 15th student thereafter.
B) The best 15 students, according to the opinion of the instructor, in a class are selected.
C) All students in a class are grouped according to their gender. A random sample of 8 is selected from the males and a separate random sample of 7 is drawn from the females.
D) The first 15 students in a class are selected without replacement.

Question 18

Which of the following yields a simple random sample?

A) All students in a class are grouped according to their gender. A random sample of 8 is selected from the males and a separate random sample of 7 is drawn from the females.
B) The best 15 students, according to the opinion of the instructor, in a class are selected.
C) The names of 50 students in a class are written on 50 different pieces of paper and put in a hat. The first 15 pieces of paper are selected blindly one at a time after shuffling the papers thoroughly and each of the selected pieces is placed back into the hat before the next piece is selected.
D) All students in a class are divided into groups according to the rows in which they are seated. One of the groups is randomly selected.

Question 19

A sample of 300 subscribers to a particular magazine is selected from a population frame of 9,000 subscribers. If, upon examining the data, it is determined that no subscriber had been selected in the sample more than once,

A) the sample could not have been random.
B) the sample may have been selected without replacement or with replacement.
C) the sample had to have been selected with replacement.
D) the sample had to have been selected without replacement.

Question 20

A company selling apparel online sends out emails every Monday to all its customers who made a purchase. This is an example of a

A) systematic sample.
B) convenience sample.
C) simple random sample.
D) stratified sample.

Question 21

Which of the following sampling methods will more likely be susceptible to ethical violation when used to form conclusions about the entire population?

A) simple random sample
B) cluster sample
C) systematic sample
D) convenience sample

Question 22

A population frame for a survey contains a listing of 72,345 names. Using a table of random numbers, how many digits will the code numbers for each member of your population contain?

A) 3
B) 4
C) 5
D) 6

Question 23

A sample is always a good representation of the target population.

Question 24

Since a ________ is not a randomly selected probability sample, there is no way to know how well it represents the overall population.

A) simple random sample
B) convenience sample
C) stratified sample
D) cluster sample

Question 25

A convenience sample is a type of probability sample.

Question 26

Sampling error can be completely eliminated by taking larger sample sizes.

Question 27

Which of the following sampling methods will more likely be susceptible to ethical violation when used to form conclusions about the entire population?

A) simple random sample
B) cluster sample
C) judgment sample
D) stratified sample

Question 28

Which of the following can be reduced by proper interviewer training?

A) sampling error
B) measurement error
C) both of the above
D) none of the above

Question 29

A population frame for a survey contains a listing of 6,179 names. Using a table of random numbers, which of the following code numbers will appear on your list?

A) 06
B) 0694
C) 6946
D) 61790

Question 30

A telemarketer set the company's computerized dialing system to contact every 25th person listed in the local telephone directory. What sampling method was used?

A) simple random sample
B) systematic sample
C) stratified sample
D) cluster sample

Question 31

Using different frames to generate data can lead to totally different conclusions.

Question 32

As a population becomes large, it is usually better to obtain statistical information from the entire population.

Question 33

Sampling error can be reduced by taking larger sample sizes.

Question 34

The only reliable way a researcher can make statistical inferences from a sample to a population is to use nonprobability sampling methods.

Question 35

There can be only one sample selected from a population.

Question 36

If a simple random sample is chosen with replacement, each individual has the same chance of selection on every selection.

Question 37

Items or individuals in a judgment sample are chosen according to their probability of occurrence.

Question 38

When dealing with human surveys, we are usually interested in sampling with replacement.

Question 39

Which of the following sampling methods will more likely be susceptible to ethical violation?

A) simple random sample
B) cluster sample
C) convenience sample
D) stratified sample

Question 40

The Dean of Students mailed a survey to a total of 400 students. The sample included 100 students randomly selected from each of the freshman, sophomore, junior, and senior classes on campus last term. What sampling method was used?

A) simple random sample
B) systematic sample
C) stratified sample
D) cluster sample

Question 41

To estimate the mean number of hours a student at a major university spent in the library, a researcher obtained the list of students from the registrar's office, from which she can select a random sample 200 students. This list is a ________.

Question 42

To gather opinions on the efficacy of U.S. foreign policies, a sample of 50 faculty members is selected from the pool of university professors who have taught political science at the graduate level. This is an example of a judgment sample.

Question 43

Measurement error will become an ethical issue when the findings are presented without reference to sample size and margin of error.

Question 44

Coverage error can become an ethical issue if a particular group is intentionally excluded from the frame.

Question 45

The question "Is your household income last year somewhere between $50,000 and $100,000?" will most likely result in coverage error.

Question 46

If you randomly select a student from the first row of a business statistics class and then every other fifth student thereafter until you get a sample of 20 students, this is an example of a convenience sample.

Question 47

An electronic appliance chain gathered customer opinions on their services using the customer feedback forms that are attached to the product registration forms. This is an example of a convenience sample.

Question 48

Measurement error can become an ethical issue when an interviewer purposely guides the responses in a particular direction.

Question 49

The sampling process begins by locating appropriate data sources called ________.

Question 50

Coverage error results in a ________.

Question 51

When participants are allowed to self-select into the sample, you have a nonprobability sample.

Question 52

You stand at the main entrance to a department store and pick the first 20 customers that enter the store after it has opened its door for business on a single day. This is an example of a systematic sample.

Question 53

Systematic samples are less efficient than a stratified sample.

Question 54

________ results from the exclusion of certain groups of subjects from a population frame.

Question 55

________ results from the failure to collect data on all subjects in the sample.

Question 56

The professor of a business statistics class wanted to find out the mean amount of time per week her students spent studying for the class. Among the 50 students in her class, 20% were freshmen, 50% were sophomores and 30% were juniors. She decided to select 2 students randomly from the freshmen, 5 randomly from the sophomores and 3 randomly from the juniors. This is an example of a systematic sample.

Question 57

The only way one can eliminate sampling error is to take the whole population as the sample.

Question 58

The question "How many times have you abused your spouse in the last six months?" will most likely result in nonresponse error.

Question 59

In a business statistics class, students sit randomly without particular preferences. A sample is selected by including everybody who sits in the first row. This is an example of a cluster sample.

Question 60

Measurement error can become an ethical issue when a survey sponsor chooses leading questions that guide the responses in a particular direction.

Question 61

The professor of a business statistics class wanted to find out the mean amount of time per week her students spent studying for the class. She divided the fifty students on her roster into ten groups starting from the first student on the roster. The first student was randomly selected from the first group. Then every tenth student was selected from the remaining students. This is an example of a cluster sample.

Question 62

The Central Limit Theorem is important in statistics because

A) for a large n, it says the population is approximately normal.
B) for any population, it says the sampling distribution of the sample mean is approximately normal, regardless of the sample size.
C) for a large n, it says the sampling distribution of the sample mean is approximately normal, regardless of the shape of the population.
D) for a sample of any size, it says the sampling distribution of the sample mean is approximately normal.

Question 63

The average score of all pro golfers for a particular course has a mean of 70 and a standard deviation of 3.0. Suppose 36 pro golfers played the course today. Find the probability that the average score of the 36 pro golfers exceeded 71.

Question 64

The professor of a business statistics class wanted to find out the mean amount of time per week her students spent studying for the class. She divided the students into the left, right, and center groups according to the location they sat in the class that day. One of these three groups was randomly selected and everyone in the group was asked the mean amount of time per week he/she spent studying for the class. This is an example of a cluster sample.

Question 65

The amount of time it takes to complete an examination has a left-skewed distribution with a mean of 65 minutes and a standard deviation of 8 minutes. If 64 students were randomly sampled, the probability that the sample mean of the sampled students exceeds 71 minutes is approximately 0.

Question 66

Which of the following is true about the sampling distribution of the sample mean?

A) The mean of the sampling distribution is always μ.
B) The standard deviation of the sampling distribution is always σ.
C) The shape of the sampling distribution is always approximately normal.
D) All of the above are true.

Question 67

Why is the Central Limit Theorem so important to the study of sampling distributions?

A) It allows us to disregard the size of the sample selected when the population is not normal.
B) It allows us to disregard the shape of the sampling distribution when the size of the population is large.
C) It allows us to disregard the size of the population we are sampling from.
D) It allows us to disregard the shape of the population when n is large.

Question 68

Sampling distributions describe the distribution of

A) parameters.
B) statistics.
C) both parameters and statistics.
D) neither parameters nor statistics.

Question 69

Suppose the ages of students in Statistics 101 follow a right-skewed distribution with a mean of 23 years and a standard deviation of 3 years. If we randomly sampled 100 students, which of the following statements about the sampling distribution of the sample mean age is incorrect?

A) The mean of the sampling distribution is equal to 23 years.
B) The standard deviation of the sampling distribution is equal to 3 years.
C) The shape of the sampling distribution is approximately normal.
D) The standard error of the sampling distribution is equal to 0.3 years.

Question 70

Which of the following statements about the sampling distribution of the sample mean is incorrect?

A) The sampling distribution of the sample mean is approximately normal whenever the sample size is sufficiently large (n ≥ 30).
B) The sampling distribution of the sample mean is generated by repeatedly taking samples of size n and computing the sample means.
C) The mean of the sampling distribution of the sample mean is equal to μ.
D) The standard deviation of the sampling distribution of the sample mean is equal to σ.

Question 71

Suppose a sample of n = 50 items is selected from a population of manufactured products and the weight, X, of each item is recorded. Prior experience has shown that the weight has a probability distribution with μ = 6 ounces and σ = 2.5 ounces. Which of the following is true about the sampling distribution of the sample mean if a sample of size 15 is selected?

A) The mean of the sampling distribution is 6 ounces.
B) The standard deviation of the sampling distribution is 2.5 ounces.
C) The shape of the sampling distribution is approximately normal.
D) All of the above are correct.

Question 72

If the expected value of a sample statistic is equal to the parameter it is estimating, then we call that sample statistic

A) unbiased.
B) minimum variance.
C) biased.
D) random.

Question 73

The Central Limit Theorem is considered powerful in statistics because it works for any population distribution provided the sample size is sufficiently large and the population mean and standard deviation are known.

Question 74

The question: "How much did you earn last year rounded to the nearest hundred dollars?" will most likely result in measurement error.

Question 75

For air travelers, one of the biggest complaints is of the waiting time between when the airplane taxis away from the terminal until the flight takes off. This waiting time is known to have a right-skewed distribution with a mean of 10 minutes and a standard deviation of 8 minutes. Suppose 100 flights have been randomly sampled. Describe the sampling distribution of the mean waiting time between when the airplane taxis away from the terminal until the flight takes off for these 100 flights.

A) Distribution is right-skewed with mean = 10 minutes and standard error = 0.8 minutes.
B) Distribution is right-skewed with mean = 10 minutes and standard error = 8 minutes.
C) Distribution is approximately normal with mean = 10 minutes and standard error = 0.8 minutes.
D) Distribution is approximately normal with mean = 10 minutes and standard error = 8 minutes.

Question 76

The question: "Have you used any form of illicit drugs over the past two months?" will most likely result in measurement error if the question is answered.

Question 77

Sampling error becomes an ethical issue if the findings are purposely presented without reference to sample size and margin of error so that the sponsor can promote a viewpoint that might otherwise be truly insignificant.

Question 78

Selection bias occurs more frequently in systematic samples than in simple random samples.

Question 79

The standard error of the mean

A) is never larger than the standard deviation of the population.
B) decreases as the sample size increases.
C) measures the variability of the mean from sample to sample.
D) all of the above

Question 80

A sample that does not provide a good representation of the population from which it was collected is referred to as a(n)________ sample.