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 parameter?

Accepted Answer

The mean income of all families in a city.

Question 3

A researcher wants to estimate the average cholesterol level of all American adults. She collects data from 1,000 randomly selected adults. In this context, what is the sample?

Accepted Answer

The 1,000 randomly selected adults.

Question 4

Which of the following best defines a statistic?

Accepted Answer

A numerical summary of a sample.

Question 5

Which of the following is a correct formula for the sample mean $$\bar{x}$$?

Accepted Answer

$$\bar{x} = \frac{\sum_{i=1}^{n} x_i}{n}$$

Question 6

A study collects data on the heights of all students in a university. Which type of data collection method is this?

Accepted Answer

Census

Question 7

Which of the following best describes an observational study?

Accepted Answer

The researcher collects data without influencing the subjects.

Question 8

A simple random sample is best described as:

Accepted Answer

A sample where every individual has an equal chance of being selected.

Question 9

Which of the following is an example of sampling bias?

Accepted Answer

Choosing survey participants only from a local gym to estimate average exercise habits.

Question 10

In a randomized experiment, what is the main purpose of random assignment?

Accepted Answer

To eliminate confounding variables by balancing them across treatment groups.

Question 11

A researcher wants to know if a new medication lowers blood pressure. She randomly assigns 100 patients to receive either the medication or a placebo. What type of study is this?

Accepted Answer

Randomized experiment

Question 12

Which of the following is a parameter, not a statistic?

Accepted Answer

The average height of all American adults.

Question 13

Which of the following best describes a confounding variable?

Accepted Answer

A variable that influences both the explanatory and response variables, making it difficult to determine causality.

Question 14

Which of the following is an example of a non-response bias?

Accepted Answer

Some individuals selected for a survey do not participate.

Question 15

A frequency table is used to:

Accepted Answer

Summarize the distribution of a single categorical variable.

Question 16

Which of the following is the correct formula for the population mean $$\mu$$?

Accepted Answer

$$\mu = \frac{\sum_{i=1}^{N} x_i}{N}$$

Question 17

Which of the following best describes the purpose of a control group in an experiment?

Accepted Answer

To provide a baseline for comparison with the treatment group.

Question 18

A researcher is interested in the effect of exercise on stress levels. She observes a group of people who exercise regularly and a group who do not, without assigning them to groups. What type of study is this?

Accepted Answer

Observational study

Question 19

Which of the following is an example of a stratified random sample?

Accepted Answer

Randomly selecting 50 students from each grade level in a high school.

Question 20

Which of the following best describes the placebo effect?

Accepted Answer

Subjects improve because they believe they are receiving treatment, even if they are not.

Chapter 1 Study Guide: Data Collection in Statistics

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