Question 1

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

Accepted Answer

A population is the entire group of individuals or items being studied, while a sample is a subset selected from the population.

Question 2

A researcher wants to study the average commute time for all employees at a large company. She randomly selects 50 employees and records their commute times. Which term best describes the 50 employees?

Accepted Answer

Sample

Question 3

Which of the following is an example of a voluntary-response sample?

Accepted Answer

A poll on a news website where visitors can choose to participate.

Question 4

A study finds that the mean income of a sample of 400 adults is $$35,000. What is the correct term for the value 35$$,000?

Accepted Answer

Statistic

Question 5

Which of the following best describes categorical data?

Accepted Answer

Data that consists of names, labels, or categories.

Question 6

The number of cars sold by a dealership each day is an example of:

Accepted Answer

Discrete data

Question 7

Which level of measurement is represented by the following data: 'low', 'medium', 'high'?

Accepted Answer

Ordinal

Question 8

A researcher divides a city into 10 districts, randomly selects 3 districts, and surveys all residents in those districts. What sampling method is this?

Accepted Answer

Cluster sampling

Question 9

Which of the following statements about statistical significance is correct?

Accepted Answer

Statistical significance is achieved when the likelihood of an event occurring by chance is 5% or less.

Question 10

A frequency distribution table is used to:

Accepted Answer

Display how data are partitioned among several categories by listing the categories and their frequencies.

Question 11

Given a class with lower class limit 10 and upper class limit 19, what is the class midpoint?

Accepted Answer

$$(10 + 19) / 2 = 14.5$$

Question 12

Which of the following best describes a histogram?

Accepted Answer

A graph of quantitative data with bars representing frequencies for classes.

Question 13

If a data set is bell-shaped and has a mean of 50 and a standard deviation of 5, according to the empirical rule, about what percentage of values fall between 45 and 55?

Accepted Answer

About 68%

Question 14

Which measure of center is most affected by extreme values (outliers)?

Accepted Answer

Mean

Question 15

A data set has a minimum value of 10 and a maximum value of 70. What is the range?

Accepted Answer

$$70 - 10 = 60$$

Question 16

A z score is calculated as $$z = \frac{x - \mu}{\sigma}. If a $$student scored 90 on a test with a mean of 80 and a standard deviation of 5, what is the student's z score?

Accepted Answer

$$z = \frac{90 - 80}{5} = 2$$

Question 17

Which of the following is NOT a property of the standard deviation?

Accepted Answer

It is a resistant measure of variation.

Question 18

A boxplot is useful for:

Accepted Answer

Displaying the five-number summary and identifying outliers.

Question 19

Which sampling method is most likely to produce a biased sample?

Accepted Answer

Convenience sampling

Question 20

In a study, researchers observe and record the eating habits of children without intervening. What type of study is this?

Accepted Answer

Observational study

Introductory Statistics: Structured Study Notes (Chapters 1–3)

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