$$\text{Standard deviation} = \sqrt{\text{variance}}$$

Question 1

Which of the following best describes a unimodal distribution?

Accepted Answer

A distribution with one peak or hump.

Question 2

Suppose you have the following data set: 3, 4, 6, 6, 7, 9, 9, 10. What is the mean of this sample?

Accepted Answer

$$\frac{3+4+6+6+7+9+9+10}{8} = 6.75$$

Question 3

What is the main disadvantage of using the mean as a measure of center in a data set with outliers?

Accepted Answer

The mean is heavily influenced by outliers.

Question 4

Given the data set: 2, 3, 7, 9, 15, 20, 27, 32, 40, 41, 50, what is the median?

Accepted Answer

The median is 20.

Question 5

For a grouped frequency distribution, what is the modal class?

Accepted Answer

The class with the largest frequency.

Question 6

If a histogram is bell-shaped and symmetric, which term best describes its distribution?

Accepted Answer

Normal

Question 7

What is the formula for the population variance?

Accepted Answer

$$\$$sigma^2$$ = \frac{\sum (x_i - \mu)^2$}{n}$$

Question 8

Which measure of spread is defined as the length of the shortest interval containing all data values?

Accepted Answer

Range

Question 9

If a distribution is skewed to the right, which statement is true about the mean and median?

Accepted Answer

The mean is to the right of the median.

Question 10

What is the standard deviation in terms of variance?

Accepted Answer

$$	ext{Standard deviation} = \sqrt{	ext{variance}}$$

Question 11

A sample of plant heights is divided into 5 classes from 12.5 cm to 20 cm. What is the class width?

Accepted Answer

$$\frac{20 - 12.5}{5} = 1.5 cm$$

Question 12

Which of the following is NOT a typical shape descriptor for a histogram?

Accepted Answer

Circular

Question 13

In a sample, the mean is calculated as $$\bar{x} = \frac{\sum x_i}{n}. $$What does $$n$$ represent?

Accepted Answer

The number of data values in the sample.

Question 14

Which measure of center is most appropriate for a highly skewed distribution?

Accepted Answer

Median

Question 15

If all values in a data set occur with equal frequency, what can be said about the mode?

Accepted Answer

There is no mode.

Question 16

Which of the following is a plausible real-world scenario for a bimodal distribution?

Accepted Answer

Heights of adult men and women in a population.

Question 17

What does the Greek letter $$\mu$$ represent in statistics?

Accepted Answer

The population mean.

Question 18

Which measure of spread is most affected by outliers?

Accepted Answer

Range

Question 19

If you want to estimate the median from a histogram, what should you do?

Accepted Answer

Choose the x value where half the area lies to the left and half to the right.

Question 20

Which of the following is the correct formula for the sample mean?

Accepted Answer

$$\bar{x} = \frac{\sum x_i}{n}$$

Chapter 3: Displaying and Summarizing Quantitative Data

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