Question 1

Which of the following best describes a uniform distribution?

Accepted Answer

The frequency of each value is evenly spread out across all values of the variable.

Question 2

A histogram of exam scores shows most students scored in the middle range, with fewer students scoring very high or very low. What is the shape of this distribution?

Accepted Answer

Bell-shaped (symmetric)

Question 3

Which of the following is TRUE about a skewed right distribution?

Accepted Answer

The tail to the right of the peak is longer than the tail to the left.

Question 4

Which type of plot is constructed by placing each observation horizontally in increasing order and placing a dot above each observation every time it is observed?

Accepted Answer

Dot plot

Question 5

In a stem-and-leaf plot, what does the 'stem' represent?

Accepted Answer

The digits to the left of the rightmost digit

Question 6

A frequency polygon uses which of the following to represent the frequencies for the classes?

Accepted Answer

Class midpoints connected by line segments

Question 7

Given class intervals 80–89 and 90–99, what is the class midpoint for 80–89?

Accepted Answer

$$\frac{80+89}{2} = 84.5$$

Question 8

Which of the following best describes a cumulative frequency distribution?

Accepted Answer

It displays the aggregate frequency of all observations less than or equal to the category or upper class limit.

Question 9

An ogive is constructed by plotting points whose x-coordinates are the upper class limits and y-coordinates are the cumulative frequencies. What is the main purpose of an ogive?

Accepted Answer

To represent the cumulative frequency or cumulative relative frequency for the class

Question 10

Which of the following is a key guideline for creating statistical graphics?

Accepted Answer

Avoid distortion and never lie about the data

Question 11

A time-series plot is most appropriate for which type of data?

Accepted Answer

Data measured at different points in time

Question 12

A three-dimensional pie chart is used to display educational attainment. What is a major problem with this type of graph?

Accepted Answer

It can distort the perceived size of categories closer to the reader

Question 13

A bar graph shows the burglary rate for July–August as 20% and for 'Other Months' as 8%. What is misleading about this representation?

Accepted Answer

It suggests that July and August each have a burglary rate of 20%, which is not true

Question 14

Why might a bar graph comparing tax rates in 2017 and 2018 be misleading if the vertical axis does not start at zero?

Accepted Answer

It exaggerates the difference between the two rates

Question 15

Which of the following is NOT a recommended guideline for creating statistical graphics?

Accepted Answer

Use more than one design in the same graphic to draw attention

Question 16

A dataset of heights of adult males is summarized in a histogram with two distinct peaks. What is the best description of the shape of this distribution?

Accepted Answer

Bimodal

Question 17

Which of the following statements about identifying the shape of a distribution is correct?

Accepted Answer

It is subjective and may require flexibility

Question 18

Suppose you have the following class intervals: 100–109, 110–119, 120–129. What is the class midpoint for 110–119?

Accepted Answer

$$\frac{110+119}{2} = 114.5$$

Question 19

Which of the following is a reason to use a stem-and-leaf plot today, despite the availability of advanced graphical engines?

Accepted Answer

It allows for easy recreation of the original data and visualization of bar graphs

Describing and Summarizing Data: Shapes, Plots, and Graphical Integrity

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