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 records the number of cars passing through an intersection each hour. What type of variable is this?

Accepted Answer

Quantitative, discrete variable

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 from 'strongly disagree' to 'strongly agree.' What is the level of measurement for this variable?

Accepted Answer

Ordinal

Question 6

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 7

A quality control engineer 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 potential source of nonresponse bias in a survey?

Accepted Answer

Some selected individuals do not respond, and their opinions differ from those who do respond

Question 9

In an 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 double-blind experiment?

Accepted Answer

Neither the subjects nor the researchers in contact with them know which treatment is being administered

Question 11

A study tracks a group of individuals over 10 years to observe the development of a disease. What type of observational study is this?

Accepted Answer

Cohort study

Question 12

Which of the following is an example of response bias?

Accepted Answer

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

Question 13

In a matched-pairs design, which of the following is true?

Accepted Answer

Experimental units are paired based on similarity, and each pair receives both treatments

Question 14

Which of the following statements about confounding variables is correct?

Accepted Answer

Confounding variables are explanatory variables whose effects cannot be distinguished from each other

Question 15

A researcher wants to study the effect of a new fertilizer on plant growth. She randomly assigns 50 plants to receive the fertilizer and 50 plants to receive no fertilizer. What type of experimental design is this?

Accepted Answer

Completely randomized design

Question 16

Which of the following best describes the placebo effect?

Accepted Answer

Subjects improve because they believe they are receiving a treatment, even if it is inactive

Question 17

Which of the following is a key step in the process of statistics?

Accepted Answer

Identifying the research objective, collecting data, describing data, and performing inference

Question 18

Suppose a researcher wants to estimate the average income of all households in a city. She divides the city into neighborhoods, randomly selects 5 neighborhoods, and surveys every household in those neighborhoods. What sampling method is this?

Accepted Answer

Cluster sampling

Question 19

Which of the following is an example of sampling bias?

Accepted Answer

Selecting only individuals who are easily accessible

Question 20

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

$$k = \frac{N}{n}$$

Chapter 1: Data Collection – Foundations of Statistical Practice

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