Question 1

Which of the following best describes the difference between a population and a sample in statistics?

Accepted Answer

A population includes all individuals of interest, while a sample is a subset of those individuals.

Question 2

A researcher wants to study the effect of a new teaching method on student performance. She randomly assigns students to two groups: one uses the new method, the other uses the traditional method. Which type of study is this?

Accepted Answer

Designed experiment

Question 3

Which of the following variables is both quantitative and discrete?

Accepted Answer

Number of cars in a parking lot

Question 4

A survey asks respondents to rate their agreement with a statement on a scale: strongly agree, agree, disagree, strongly disagree. What is the level of measurement for this variable?

Accepted Answer

Ordinal

Question 5

Which sampling method involves dividing the population into nonoverlapping groups and then taking a simple random sample from each group?

Accepted Answer

Stratified sampling

Question 6

A researcher selects every 10th person from a list of hospital patients to participate in a study. What type of sampling method is this?

Accepted Answer

Systematic sampling

Question 7

Which of the following is an example of response bias in a survey?

Accepted Answer

Respondents give answers they think are socially acceptable rather than their true opinions.

Question 8

Suppose a study measures the income (in dollars) of participants. What is the level of measurement for this variable?

Accepted Answer

Ratio

Question 9

A school administrator randomly selects 5 classes and surveys all students in those classes. Which sampling method is being used?

Accepted Answer

Cluster sampling

Question 10

Which of the following best describes a lurking variable?

Accepted Answer

A variable not considered in a study that affects the value of the response variable.

Question 11

A researcher wants to estimate the average commute time for all employees at a large company. She obtains a list of all employees and randomly selects 50 to survey. What type of sample is this?

Accepted Answer

Simple random sample

Question 12

Which of the following is an example of a continuous variable?

Accepted Answer

Time spent studying for an exam (in hours)

Question 13

A study finds that people who exercise regularly have lower rates of heart disease. However, the study did not account for diet. What type of variable is diet in this context?

Accepted Answer

Lurking variable

Question 14

Which of the following best describes sampling bias?

Accepted Answer

The technique used to obtain the sample favors one part of the population over another.

Question 15

A researcher wants to study the effect of a new medication. She randomly assigns patients to receive either the medication or a placebo and compares their outcomes. What is the explanatory variable in this study?

Accepted Answer

Whether the patient received the medication or placebo

Question 16

Which of the following is a key difference between a case-control study and a cohort study?

Accepted Answer

Case-control studies are retrospective, while cohort studies are prospective.

Question 17

A researcher collects data on the number of siblings each student in a class has. What type of variable is this?

Accepted Answer

Quantitative, discrete

Question 18

Which of the following is an example of nonresponse bias?

Accepted Answer

People selected for a survey who do not respond have different opinions from those who do respond.

Question 19

A variable is measured at the interval level if:

Accepted Answer

It has meaningful differences between values, but a value of zero does not mean the absence of the quantity.

Question 20

A polling firm uses robocalls to landline phones to collect survey responses. Which type of error is most likely to occur as a result?

Accepted Answer

Sampling bias due to undercoverage

Chapter 1: Data Collection – Introductory Statistics Study Notes

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