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 the population.

Question 2

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

Accepted Answer

Favorite type of cuisine

Question 3

A researcher measures the time (in seconds) it takes for students to complete a puzzle. What type of variable is 'time'?

Accepted Answer

Quantitative, continuous

Question 4

Which level of measurement allows for meaningful ratios and has a true zero?

Accepted Answer

Ratio

Question 5

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

Accepted Answer

Ordinal

Question 6

Which sampling method involves dividing the population into groups and then randomly selecting all individuals from some of those groups?

Accepted Answer

Cluster sampling

Question 7

A quality control manager selects every 10th item off a production line for inspection. What type of sampling is this?

Accepted Answer

Systematic sampling

Question 8

Which of the following is a source of non-sampling error?

Accepted Answer

Sampling bias from undercoverage

Question 9

In a designed experiment, what is the purpose of a control group?

Accepted Answer

To serve as a baseline for comparison with other treatments

Question 10

Which of the following best describes a matched-pairs design?

Accepted Answer

Subjects are paired based on similarity and each pair receives both treatments in random order

Question 11

A researcher wants to study the effect of a new drug on blood pressure. She randomly assigns 100 patients to receive either the drug or a placebo. What type of study is this?

Accepted Answer

Designed experiment

Question 12

Which of the following statements about observational studies is TRUE?

Accepted Answer

They can only establish association, not causation.

Question 13

Suppose a researcher collects data on the number of books read by students in a month. What type of variable is 'number of books read'?

Accepted Answer

Quantitative, discrete

Question 14

Which of the following is an example of response bias?

Accepted Answer

Respondents giving socially desirable answers instead of truthful ones

Question 15

A study tracks a group of smokers and non-smokers over 20 years to compare rates of lung cancer. What type of observational study is this?

Accepted Answer

Cohort study

Question 16

Which formula would you use to determine the sampling interval $$k in $$systematic sampling, given a population size $$N$$ and desired sample size $$n$$?

Accepted Answer

$$k = N / n$$

Question 17

In a randomized block design, what is the main purpose of blocking?

Accepted Answer

To group similar experimental units together to reduce variability

Question 18

Which of the following is an example of a variable at the interval level of measurement?

Accepted Answer

Temperature in Celsius

Question 19

A researcher wants to estimate the average commute time for all employees at a large company. She divides employees into departments and randomly selects 5 employees from each department. What sampling method is this?

Accepted Answer

Stratified sampling

Question 20

Which of the following best describes the placebo effect in an experiment?

Accepted Answer

Subjects experience changes simply because they believe they are receiving a treatment

Chapter 1: Data Collection – Foundations of Statistical Thinking and Sampling Methods

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