Question 1

Which of the following is NOT a reason why histograms are different from bar charts?

Accepted Answer

Bars in histograms can be reordered to show different patterns.

Question 2

A researcher is analyzing earthquake magnitudes from 2000 B.C.E. to the present. Which plot would best preserve individual values while showing the distribution?

Accepted Answer

Stem-and-leaf plot

Question 3

Given the data set: 3, 4, 5, 6, 6, 6, 7, 98, what is the median?

Accepted Answer

$$6$$

Question 4

Which measure of centre is most appropriate for a distribution with significant outliers?

Accepted Answer

Median

Question 5

What is the formula for the sample variance?

Accepted Answer

$$s^2$$ = \frac{\sum (y - \bar{y}$$)^2$$}{n-1}$$

Question 6

A boxplot is constructed using which summary statistics?

Accepted Answer

Minimum, Q1, median, Q3, maximum

Question 7

If a histogram has two distinct peaks, how is its modality described?

Accepted Answer

Bimodal

Question 8

Which measure of spread is most affected by a single extreme value?

Accepted Answer

Range

Question 9

For a symmetric, unimodal distribution, approximately what percent of data falls within two standard deviations of the mean?

Accepted Answer

$$95\%$$

Question 10

Which of the following is NOT a step in constructing a boxplot?

Accepted Answer

Plot the mean as a central dot inside the box.

Question 11

A dotplot is most useful for:

Accepted Answer

Displaying individual values of a quantitative variable

Question 12

If a distribution is skewed right, which statement is true?

Accepted Answer

The mean is greater than the median.

Question 13

Which formula correctly calculates the sample standard deviation?

Accepted Answer

$$s = \sqrt{\frac{\sum (y - \bar{y})^2$}{n-1}}$$

Question 14

Which measure of spread should be used for a distribution with outliers?

Accepted Answer

Interquartile Range (IQR)

Question 15

In a five-number summary, what does Q1 represent?

Accepted Answer

The 25th percentile

Question 16

A histogram of earthquake magnitudes shows a single central peak and is symmetric. Which measure of centre and spread is most appropriate?

Accepted Answer

Mean and standard deviation

Question 17

What is the main disadvantage of using the range as a measure of spread?

Accepted Answer

It can be very large due to a single extreme value.

Question 18

Which of the following is a correct interpretation of a boxplot with the median closer to Q1 than Q3?

Accepted Answer

The distribution is skewed right.

Question 19

If the data values are tightly clustered around the centre, what can be said about the IQR and standard deviation?

Accepted Answer

Both will be small.

Question 20

Which of the following is NOT a recommended practice when displaying quantitative data?

Accepted Answer

Making a histogram of a categorical variable

Displaying and Summarizing Quantitative Data

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