Question 1

Which of the following best describes a simple random sample (SRS)?

Accepted Answer

A sample where every unit has an equal chance of selection, implemented via random number generators.

Question 2

A researcher wants to study the effect of a new medication. Participants are randomly assigned to either receive the medication or a placebo. What principle of experimental design is being used?

Accepted Answer

Random assignment

Question 3

Which of the following is an example of coverage bias?

Accepted Answer

A survey is sent only to people with landline phones, missing those who only use cell phones.

Question 4

In a stratified sampling design, what is the main advantage?

Accepted Answer

It guarantees that key subgroups are represented proportionally in the sample.

Question 5

A company wants to estimate the average salary of its employees. They divide employees into departments and randomly select some departments, then survey all employees in those departments. What sampling method is this?

Accepted Answer

Cluster sampling

Question 6

Which of the following is a key difference between observational studies and experiments?

Accepted Answer

Experiments deliberately manipulate variables, while observational studies do not.

Question 7

A survey asks, 'Do you agree that our university should reduce tuition fees and improve campus facilities?' What type of survey question is this?

Accepted Answer

Double-barreled question

Question 8

Which of the following best illustrates voluntary response bias?

Accepted Answer

A survey is mailed to all alumni, but only those with strong opinions respond.

Question 9

Suppose you want to estimate the average commute time for all employees in a city. You randomly select 10 companies and survey all employees in those companies. Which sampling method are you using?

Accepted Answer

Cluster sampling

Question 10

Which principle of experimental design helps to ensure that the results are not due to random chance by repeating the experiment on multiple subjects?

Accepted Answer

Replication

Question 11

A researcher divides a population into males and females, then randomly selects 50 males and 50 females to participate in a study. What sampling method is this?

Accepted Answer

Stratified sampling

Question 12

Which of the following is an example of confounding in an observational study?

Accepted Answer

A study finds a correlation between coffee consumption and heart disease, but age is related to both variables.

Question 13

What is the main purpose of blocking in experimental design?

Accepted Answer

To group similar units and randomize within each group to control a nuisance factor.

Question 14

Which of the following best describes systematic sampling?

Accepted Answer

Selecting every $$kth $$unit from an ordered list after a random start.

Question 15

A researcher wants to study the opinions of disabled students using university services. She purposely selects students with varied needs to get a range of perspectives. What sampling method is this?

Accepted Answer

Purposive sampling

Question 16

Which of the following is a common effect of increasing sample size in probability sampling?

Accepted Answer

Sampling error decreases.

Question 17

A survey is distributed to students in a class because they are easy to reach. What type of sampling is this?

Accepted Answer

Convenience sampling

Question 18

Which of the following is an example of a leading question?

Accepted Answer

Don’t you think our university should reduce tuition fees?

Question 19

Which of the following best describes the concept of replication in experimental design?

Accepted Answer

Repeating the same treatment on multiple experimental units to estimate variability.

Question 20

A study finds a strong correlation between shoe size and reading ability among children, but this is actually due to age. What is this an example of?

Accepted Answer

Confounding

Collecting Data: Sampling Methods, Experimental Design, and Sources of Bias

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