Question 1

A stock analyst compares the relationship between stock prices and earnings per share to help him select a stock for investment.

Accepted Answer

This is an observational study as the stock analyst is only observing and comparing the relationship between stock prices and earnings per share without intervening or manipulating any variables.

Question 2

Provide an appropriate response.
-The personnel manager at a company wants to investigate job satisfaction among the female employees. One evening after a meeting she talks to all 30 female employees who attended the meeting. Does this sampling plan
Result in a random sample? Simple random sample? Explain.

Accepted Answer

The sample is not random because only those who attended the meeting were considered, excluding those who did not attend. It is not a simple random sample because not all possible samples of 30 female employees could be selected, as it excludes those not present at the meeting.

Question 3

Provide an appropriate response.
-A researcher obtains an alphabetical list of the 2560 students at a college. She uses a random number generator to obtain 50 numbers between 1 and 2560. She chooses the 50 students corresponding to those numbers. Does
This sampling plan result in a random sample? Simple random sample? Explain.

Accepted Answer

The sampling plan results in a random sample because each student has an equal chance of being selected. It is also a simple random sample because every possible sample of 50 students has the same probability of being chosen.

Question 4

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience.
-49, 34, and 48 students are selected from the Sophomore, Junior, and Senior classes with 496, 348, and 481 students respectively.

Accepted Answer

This is an example of stratified sampling because the population (students) has been divided into strata (sophomore, junior, and senior classes) and a sample size proportional to the stratum size has been selected from each stratum. This helps ensure that the sample is representative of the overall population.

Question 5

A stock analyst selects a stock from a group of twenty for investment by choosing the stock with the greatest earnings per share reported for the last quarter.

Accepted Answer

An observational study involves observing and measuring specific characteristics without attempting to modify the subjects being studied. The analyst is simply observing the earnings per share and making a decision based on that observation.

Question 6

A doctor induces a cardiac stress test to determine the reason for a patient's illness.

Accepted Answer

A cardiac stress test is a medical procedure that is performed as an experiment to measure the response of the patient's heart to physical exertion. It involves inducing exercise or medication to increase the patient's heart rate, which allows the doctor to observe the heart's performance and diagnose any underlying conditions.

Question 7

Provide an appropriate response.
-An education expert is researching teaching methods and wishes to interview teachers from a particular school district. She randomly selects ten schools from the district and interviews all of the teachers at the selected
Schools. Does this sampling plan result in a random sample? Simple random sample? Explain.

Accepted Answer

The sample is random because all teachers have the same chance of being selected. However, it is not a simple random sample because some samples are not possible, such as a sample that includes teachers from schools that were not selected.

Question 8

Provide an appropriate response.
-A polling company obtains an alphabetical list of names of voters in a precinct. They select every 20th person from the list until a sample of 100 is obtained. They then call these 100 people. Does this sampling plan result in
A random sample? Simple random sample? Explain.

Accepted Answer

The sampling plan is not random because not all voters have the same chance of being selected; for example, the second person on the list cannot be chosen. It is also not a simple random sample because not all possible samples of 100 voters can be selected, such as those including the second person on the list.

Question 9

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience.
-A pollster uses a computer to generate 500 random numbers, then interviews the voters corresponding to those numbers.

Accepted Answer

The type of sampling used in this scenario is random sampling because the pollster is generating random numbers to select the voters to be interviewed.

Question 10

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience.
-To avoid working late, a quality control analyst simply inspects the first 100 items produced in a day.

Accepted Answer

The sampling method used is convenience sampling because the analyst is selecting items that are easily accessible and convenient to inspect, rather than using a more rigorous sampling method such as random or stratified.

Question 11

A T.V. show's executives raised the fee for commercials following a report that the show received a "No. 1" rating in a survey of viewers.

Accepted Answer

This scenario describes an observational study because the executives are simply observing the results of a survey and making a decision based on that data. There is no manipulation of variables or controlled conditions, which would be necessary for an experiment.

Question 12

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience.
-A sample consists of every 49th student from a group of 496 students.

Accepted Answer

This is an example of systematic sampling since every 49th student is selected from a group of known size (496).

Question 13

A T.V. show's executives commissioned a study to gauge the impact of the show's ratings on the sales of its advertisers.

Accepted Answer

This is an observational study because the executives are observing the relationship between the show's ratings and the sales of its advertisers, without manipulating any variables or implementing any interventions.

Question 14

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience.
-A researcher interviews 19 work colleagues who work in his building.

Accepted Answer

This is a convenience sampling method as the researcher has only selected those colleagues who work in the same building as the researcher. Therefore, the sample is not selected at random or according to any specific stratification or cluster method. A systematic sampling method would involve selecting individuals at regular intervals from a list or population.

Question 15

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience.
-The name of each contestant is written on a separate card, the cards are placed in a bag, and three names are picked from the bag.

Accepted Answer

This is an example of a random sampling method because each card has an equal chance of being picked from the bag, and there is no specific criteria for selecting the cards.

Question 16

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience.
-A market researcher selects 500 drivers under 30 years of age and 500 drivers over 30 years of age.

Accepted Answer

The market researcher is dividing the population into two strata: drivers under 30 and drivers over 30. Then, taking a random sample from each stratum. This is known as stratified sampling.

Question 17

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience.
-An education researcher randomly selects 48 middle schools and interviews all the teachers at each school.

Accepted Answer

This is an example of cluster sampling because the researcher divided the population into clusters (middle schools) and then randomly chose a sample from those clusters (all the teachers at each selected school). This is different from stratified sampling, which would involve dividing the population into subgroups based on some characteristic (such as grade level at the school) and then randomly selecting a sample from each subgroup.

Question 18

Provide an appropriate response.
-A psychology student wishes to investigate differences in political opinions between business majors and political science majors at her college. She randomly selects 100 students from the 260 business majors and 100
Students from the 180 political science majors. Does this sampling plan result in a random sample? Simple
Random sample? Explain.

Accepted Answer

The sampling plan is not random because political science majors have a higher probability of being selected compared to business majors. It is not a simple random sample because not all possible samples of the same size have an equal chance of being selected, such as a sample with 50 business majors and 150 political science majors.

Question 19

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience.
-A tax auditor selects every 1000th income tax return that is received.

Accepted Answer

The selection of every 1000th income tax return is a systematic sampling method where the sample is selected based on a fixed interval.

Question 20

Provide an appropriate response.
-A computer company employs 100 software engineers and 100 hardware engineers. The personnel manager randomly selects 20 of the software engineers and 20 of the hardware engineers and questions them about
Career opportunities within the company. Does this sampling plan result in a random sample? Simple random
Sample? Explain.

Accepted Answer

The sample is random because each software engineer has an equal chance of being selected from the software group, and each hardware engineer has an equal chance from the hardware group. However, it is not a simple random sample because not all combinations of 40 engineers are possible, such as selecting 30 software and 10 hardware engineers.

Quiz 1: Introduction to Statistics

A stock analyst compares the relationship between stock prices and earnings per share to help him select a stock for investment.

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. -49, 34, and 48 students are selected from the Sophomore, Junior, and Senior classes with 496, 348, and 481 students respectively.

A stock analyst selects a stock from a group of twenty for investment by choosing the stock with the greatest earnings per share reported for the last quarter.

A doctor induces a cardiac stress test to determine the reason for a patient's illness.

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. -A pollster uses a computer to generate 500 random numbers, then interviews the voters corresponding to those numbers.

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. -To avoid working late, a quality control analyst simply inspects the first 100 items produced in a day.

A T.V. show's executives raised the fee for commercials following a report that the show received a "No. 1" rating in a survey of viewers.

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. -A sample consists of every 49th student from a group of 496 students.

A T.V. show's executives commissioned a study to gauge the impact of the show's ratings on the sales of its advertisers.

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. -A researcher interviews 19 work colleagues who work in his building.

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. -The name of each contestant is written on a separate card, the cards are placed in a bag, and three names are picked from the bag.

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. -A market researcher selects 500 drivers under 30 years of age and 500 drivers over 30 years of age.

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. -An education researcher randomly selects 48 middle schools and interviews all the teachers at each school.

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. -A tax auditor selects every 1000th income tax return that is received.