Question 1

Which of the following best describes a histogram?

Accepted Answer

A graphical display of data using bars of different heights to show the frequency of data in equal intervals.

Question 2

A boxplot is useful for which of the following purposes?

Accepted Answer

Displaying the five-number summary and identifying outliers in a dataset.

Question 3

Given a dataset with a mean of 10 and a standard deviation of 2, what is the z-score for a value of 14?

Accepted Answer

$z = \frac{14 - 10}{2} = 2$

Question 4

Which of the following is NOT part of the five-number summary?

Accepted Answer

Mean

Question 5

If a dataset is skewed to the right, which of the following is most likely true?

Accepted Answer

The mean is greater than the median.

Question 6

A researcher collects the following data: 2, 4, 4, 6, 8. What is the median?

Accepted Answer

4

Question 7

Which of the following best describes an outlier in a boxplot?

Accepted Answer

A data point that lies more than 1.5 times the interquartile range above Q3 or below Q1.

Question 8

Suppose the mean of a dataset is 20 and the standard deviation is 5. What is the value at the 84th percentile, assuming a normal distribution?

Accepted Answer

$20 + 1 	imes 5 = 25$

Question 9

Which of the following is the correct formula for the z-score?

Accepted Answer

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

Question 10

A student scores 85 on a test with a mean of 80 and a standard deviation of 5. What is the student's z-score?

Accepted Answer

$z = \frac{85 - 80}{5} = 1$

Question 11

Which of the following is true about the interquartile range (IQR)?

Accepted Answer

It measures the spread of the middle 50% of the data.

Question 12

If a boxplot shows a long whisker on the right side, what does this indicate about the data?

Accepted Answer

The data is skewed to the right.

Question 13

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

Accepted Answer

It is skewed to the right.

Question 14

A dataset has Q1 = 12, Q3 = 20. What is the interquartile range (IQR)?

Accepted Answer

$IQR = 20 - 12 = 8$

Question 15

Which of the following best describes the median?

Accepted Answer

The value that divides the dataset into two equal halves.

Question 16

If a value is more than 3 standard deviations from the mean in a normal distribution, what can you conclude?

Accepted Answer

It is considered an extreme outlier.

Review of Graphical and Numerical Data Description in Statistics

Study Guide - Practice Questions