Question 1

Which of the following best describes the distribution shown in the third image (green histogram with IQ scores)?

Accepted Answer

Symmetrical – Bell Shaped (Normal Distribution)

Question 2

A frequency distribution is constructed for the weights of pennies. If there is a large gap between the lightest and heaviest pennies, what does this most likely indicate?

Accepted Answer

The data come from two different populations

Question 3

Given a class with lower class limit 70 and upper class limit 89, what is the class midpoint?

Accepted Answer

$$\frac{70 + 89}{2} = 79.5$$

Question 4

Which graph type is best for showing the trend of the Dow Jones Industrial Average over several decades, as seen in image 11?

Accepted Answer

Time-series graph

Question 5

What is the main difference between a histogram and a bar graph?

Accepted Answer

A histogram has bars that touch, representing continuous data, while a bar graph has separated bars for categorical data.

Question 6

If the class frequencies in a relative frequency histogram are 0.2, 0.3, 0.4, and 0.1, what is the sum of the relative frequencies?

Accepted Answer

$$0.2 + 0.3 + 0.4 + 0.1 = 1.0$$

Question 7

Which of the following graphs is most appropriate for displaying the distribution of pulse rates of males, as shown in image 9?

Accepted Answer

Dotplot

Question 8

A distribution is said to be skewed to the right if:

Accepted Answer

It has a longer right tail

Question 9

Which graph type is used to show the frequencies of categories in descending order, as seen in image 14?

Accepted Answer

Pareto chart

Question 10

If a frequency distribution has class boundaries of 49.5, 69.5, 89.5, 109.5, 129.5, and 149.5, what is the class width?

Accepted Answer

$$69.5 - 49.5 = 20$$

Question 11

Which of the following is a key characteristic of a normal distribution?

Accepted Answer

The distribution is bell-shaped and symmetric

Question 12

What does a cumulative frequency distribution show?

Accepted Answer

The sum of frequencies up to and including each class

Question 13

Which graph would best help you determine if there is a correlation between two quantitative variables?

Accepted Answer

Scatterplot

Question 14

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

Accepted Answer

The leftmost digit(s) of each value

Question 15

Which of the following is a potential problem with pictographs in statistical presentations?

Accepted Answer

They can exaggerate differences due to the size of the images

Question 16

A time-series graph is most useful for which type of data?

Accepted Answer

Quantitative data collected over different points in time

Question 17

If a histogram shows a uniform distribution, what does this mean about the frequencies?

Accepted Answer

Frequencies are equal across all classes

Question 18

Which of the following is true about correlation as shown in a scatterplot?

Accepted Answer

A positive correlation means as $$x$$ increases, $$y$$ increases

Question 19

If the class frequency for a class is 15 and the sum of all frequencies is 60, what is the relative frequency for that class?

Accepted Answer

$$\frac{15}{60} = 0.25$$

Question 20

Which graph type is best for showing the proportion of different food groups in a recommended diet, as seen in image 15?

Accepted Answer

Pie chart

Exploring Data with Graphs: Frequency Distributions and Graphical Methods in Statistics

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