Question 1

Which of the following best describes the difference between a population and a sample in statistics?

Accepted Answer

A population includes all members of a group, while a sample is a part of that group.

Question 2

A researcher wants to estimate the average salary of all employees at a large company. She randomly selects 50 employees and calculates their average salary. In this context, what is the statistic?

Accepted Answer

The average salary calculated from the 50 selected employees.

Question 3

Which sampling method is most likely to introduce bias if used to estimate the average income of residents in a city?

Accepted Answer

Convenience sampling

Question 4

A survey asks, 'How strongly do you agree that our award-winning professor is the best teacher?' What type of bias is most likely present in this question?

Accepted Answer

Response bias

Question 5

Which of the following is an example of a stratified sampling method?

Accepted Answer

Dividing students into freshmen and sophomores, then randomly sampling from each group.

Question 6

A study finds that a new medication reduces blood pressure by an average of 2 mmHg, with a p-value less than 0.01. Which of the following is true?

Accepted Answer

The result is statistically significant but may not be practically significant.

Question 7

Calculate the sample proportion $$\hat{p}$$ for the following scenario: Out of 75 participants, 50 agreed with the statement 'Things are more expensive.'

Accepted Answer

$$\hat{p} = \frac{50}{75} = 0.67$$

Question 8

Which of the following is an example of a discrete quantitative variable?

Accepted Answer

Number of cars in a parking lot

Question 9

What is the main difference between an experiment and an observational study?

Accepted Answer

Experiments involve applying a treatment, while observational studies do not.

Question 10

A researcher divides a city into neighborhoods and randomly selects three neighborhoods. She then surveys every household in those neighborhoods. What sampling method is this?

Accepted Answer

Cluster sampling

Question 11

Which of the following best describes nonresponse bias?

Accepted Answer

When individuals who do not respond differ in important ways from those who do respond

Question 12

Which of the following variables is categorical and nominal?

Accepted Answer

Eye color

Question 13

A poll is conducted by asking people who visit a particular website to respond. What is the main issue with this sampling method?

Accepted Answer

It is a voluntary response sample and likely to be biased.

Question 14

Which of the following is an example of an ordinal variable?

Accepted Answer

Letter grades (A, B, C, D, F)

Question 15

Why is randomization important in sampling?

Accepted Answer

It helps ensure the sample is representative of the population.

Question 16

Which of the following best describes a parameter?

Accepted Answer

A numerical summary of a population

Question 17

A survey is conducted at a college by interviewing students who are in the cafeteria at noon. What is the main problem with this sampling method?

Accepted Answer

It is a convenience sample and may not represent all students.

Question 18

Which of the following is an example of practical significance without statistical significance?

Accepted Answer

A new teaching method increases test scores by 0.1 points on average, but the result is not statistically significant.

Question 19

Which formula is used to calculate the sample proportion $$\hat{p}$$?

Accepted Answer

$$\hat{p} = \frac{	ext{number meeting criteria}}{	ext{total sampled}}$$

Question 20

Which of the following is a continuous quantitative variable?

Accepted Answer

Height of a person

Introduction to Statistics: Foundations, Sampling, and Data Types

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