Question 1

Which of the following best describes anecdotal evidence?

Accepted Answer

Data based on individual experiences or observations that are emotionally persuasive but scientifically weak.

Question 2

A researcher wants to study the effect of a new drug on blood pressure. She randomly assigns participants to receive either the drug or a placebo and measures their blood pressure after treatment. What type of study is this?

Accepted Answer

Designed experiment

Question 3

In the context of sampling, what is the main problem illustrated by the Literary Digest poll in the 1936 election?

Accepted Answer

The sample was not representative of the population due to sampling bias.

Question 4

Which of the following is a confounding variable in the study of ice cream sales and drowning deaths?

Accepted Answer

Temperature

Question 5

A battery manufacturer inspects 24 batteries each day for defects. What is the population and what is the sample in this scenario?

Accepted Answer

Population: all batteries produced; Sample: 24 batteries inspected each day

Question 6

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

Accepted Answer

Stratified sampling

Question 7

What is the key difference between cluster sampling and stratified sampling?

Accepted Answer

Cluster sampling samples all individuals in selected clusters, while stratified sampling samples from each stratum.

Question 8

Which of the following is NOT a common source of sampling bias?

Accepted Answer

Simple random sampling

Question 9

Why is implied randomness important in statistical sampling?

Accepted Answer

It makes statistical estimates and errors reliable.

Question 10

Suppose you want to estimate the average income of residents in a city. You only survey people at a luxury shopping mall. What type of sampling bias is most likely present?

Accepted Answer

Convenience sampling bias

Question 11

Which of the following best describes a parameter?

Accepted Answer

A numerical summary of a population.

Question 12

A survey asks, 'Is US spending too much on welfare?' versus 'Is US spending too much on assistance to the poor?' What issue does this illustrate?

Accepted Answer

Importance of wording of questions

Question 13

Which of the following is true about simple random sampling (SRS)?

Accepted Answer

Every individual in the population has an equal chance of being selected.

Question 14

In a multistage sampling design, which step is added to cluster sampling?

Accepted Answer

Take a simple random sample of observations from each chosen cluster.

Question 15

A researcher surveys only registered automobile owners and telephone users during the Great Depression. What is the most likely consequence?

Accepted Answer

The sample will over-represent individuals with higher incomes.

Question 16

Which of the following is an example of undercoverage?

Accepted Answer

Sampling by housing units may miss the homeless.

Question 17

Why are experiments generally preferred over observational studies for establishing causation?

Accepted Answer

Experiments can control for confounding variables.

Question 18

Which formula represents the probability of selecting a specific individual in a simple random sample of size $$n$$ from a population of size $$N$$?

Accepted Answer

$$P = \frac{1}{N}$$

Question 19

A survey is conducted by asking people to respond online if they are interested. What type of bias is most likely to affect the results?

Accepted Answer

Voluntary response bias

Question 20

Which of the following best illustrates response bias?

Accepted Answer

Respondents answer in a way to please the interviewer or hide certain behaviors.

Lecture 2: Collecting Data – Foundations of Statistical Sampling and Study Design

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