Question 1

Which of the following best describes the difference between a parameter and a statistic?

Accepted Answer

A parameter is a numerical summary of a population, while a statistic is a numerical summary of a sample.

Question 2

A pharmaceutical company wants to test a new drug. They randomly assign 100 patients to receive the drug and 100 to receive a placebo. What type of study is this?

Accepted Answer

Experimental study

Question 3

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

Accepted Answer

The number of cars in a parking lot

Question 4

A researcher collects data on the favorite ice cream flavors of 200 students. What level of measurement is this data?

Accepted Answer

Nominal

Question 5

Which sampling method is used when every member of a population has an equal chance of being selected?

Accepted Answer

Simple random sampling

Question 6

Given the following data set: 2, 4, 4, 6, 8, what is the mean?

Accepted Answer

$$\frac{2+4+4+6+8}{5} = 4.8$$

Question 7

Which of the following graphs is most appropriate for displaying the distribution of a categorical variable?

Accepted Answer

Bar chart

Question 8

If a distribution is skewed to the right, which of the following is true?

Accepted Answer

The mean is greater than the median.

Question 9

A boxplot is useful for identifying which of the following?

Accepted Answer

The presence of outliers in a data set

Question 10

Which formula correctly calculates the variance $$s^2 of a $$sample with $$n$$ observations $$x_1$$, $$x_2$$, ..., x_n$$ and sample mean $$\bar{x}$$?

Accepted Answer

$$s^2$$ = \frac{\sum_{i=1}^n (x_i - \bar{x}$$)^2$$}{n-1}$$

Question 11

A researcher wants to estimate the average commute time for all employees at a large company. She randomly selects 50 employees and records their commute times. What is the population in this scenario?

Accepted Answer

All employees at the company

Question 12

Which of the following is NOT a characteristic of a normal distribution?

Accepted Answer

It is skewed to the right.

Question 13

If the probability of rain tomorrow is 0.3, what is the probability that it will not rain?

Accepted Answer

$$1 - 0.3 = 0.7$$

Question 14

Which of the following best describes the empirical rule for a normal distribution?

Accepted Answer

All of the above.

Question 15

A student scores 1.5 standard deviations above the mean on a test. What is the student's z-score?

Accepted Answer

$$z = 1.5$$

Question 16

Which of the following is an example of stratified sampling?

Accepted Answer

Dividing a population into groups based on age and randomly sampling from each group

Question 17

Which formula is used to calculate the z-score for a value $$x in a $$population with mean $$\mu$$ and standard deviation $$\sigma$$?

Accepted Answer

$$z = \frac{x - \mu}{\sigma}$$

Question 18

A data set has a mean of 50 and a standard deviation of 5. What is the z-score for a value of 60?

Accepted Answer

$$z = \frac{60 - 50}{5} = 2$$

Question 19

Which of the following is a property of the median?

Accepted Answer

It divides the data set into two equal halves.

Question 20

Which of the following best describes a conditional probability?

Accepted Answer

The probability of an event occurring given that another event has already occurred.

Introductory Statistics Study Guide – Step-by-Step Guidance

Study Guide - Practice Questions

Study Guide - Flashcards