Question 1

When constructing any graphical display that utilizes categorical data,classes that have frequencies of 5 percent or less are usually combined together into a single category.

Accepted Answer

This is a common practice to simplify the display and avoid having too many categories with low frequencies.

Question 2

In the first step of setting up a Pareto chart,a frequency table should be constructed of the defects (or categories)in decreasing order of frequency.

Accepted Answer

This is true. The first step in creating a Pareto chart is to identify the categories or defects and construct a frequency table in descending order of occurrence.

Question 3

The stem-and-leaf display is advantageous because it allows us to actually see the measurements in the data set.

Accepted Answer

The stem-and-leaf display is a visual representation of the data set that allows us to see the individual measurements in a clear and organized way. This makes it easier to identify patterns, outliers, and other key features of the data.

Question 4

It is possible to create different interpretations of the same graphical display by simply using different captions.

Accepted Answer

Captions can provide context and emphasize different aspects of a graphical display, leading to different interpretations by the audience.

Question 5

A stem-and-leaf display is a graphical portrayal of a data set that shows the data set's overall pattern of variation.

Accepted Answer

This statement is true. A stem-and-leaf display is a type of graph that organizes data in a way that allows patterns in the data set to be easily seen. It uses the first digit(s) (or stem) to group the data and the last digit (or leaf) to represent individual values within each group. This makes it useful for displaying numerical data sets, such as test scores or temperatures.

Question 6

When looking at the shape of the distribution using a stem-and-leaf,a distribution is skewed to the right when the left tail is shorter than the right tail.

Accepted Answer

The answer of When looking at the shape of the...

Question 7

Beginning the vertical scale of a graph at a value different from zero can cause increases to look more dramatic.

Accepted Answer

Beginning the vertical scale at a higher value can exaggerate the differences between values, making changes look more dramatic than they actually are.

Question 8

Each stem of a stem-and-leaf display should be a single digit.

Accepted Answer

Leaves on the stem-and-leaf are a single digit.

Question 9

The sample cumulative distribution function is nondecreasing.

Accepted Answer

The definition of a cumulative distribution function states that it must be nondecreasing. This means that the function must either stay the same or increase as the input values increase. Therefore, the statement is true.

Question 10

When establishing the classes for a frequency table,it is generally agreed that the more classes you use the better your frequency table will be.

Accepted Answer

While it may seem that more classes would give greater detail in a frequency table, having too many classes can also lead to overcomplication and make the data harder to interpret. It is important to find a balance between having enough classes to accurately represent the data and not having too many that it becomes overwhelming.

Question 11

When data are qualitative,the bars should never be separated by gaps.

Accepted Answer

Bar graphs for qualitative data are displayed with a gap between each category.

Question 12

A runs plot is a form of scatter plot.

Accepted Answer

A runs plot is a specific type of scatter plot that shows the distribution of runs scored by a team in each inning of a baseball game.

Question 13

In a Pareto chart,the bar for the "Other" category should be placed to the far left of the chart.

Accepted Answer

The bar for the "Other" category should be placed at the end of the chart, after all the other bars have been displayed in descending order of frequency or magnitude. This allows for a clear visualization of the cumulative impact of the top categories on the overall data set.

Question 14

A bar chart is a graphic that can be used to depict qualitative data.

Accepted Answer

A bar chart is a graphic that depicts a frequency, relative frequency, or percent frequency distribution.

Question 15

Stem-and-leaf displays and dot plots are useful for detecting outliers.

Accepted Answer

Both stem-and-leaf displays and dot plots provide a visual representation of data that can make outliers more apparent. In a stem-and-leaf display, any values that are significantly separated from the rest of the data are easily identifiable. In a dot plot, outliers present themselves as individual data points that are far away from the rest of the distribution.

Question 16

A scatter plot can be used to identify outliers.

Accepted Answer

A scatter plot is used to identify the relationship between two variables.

Question 17

The relative frequency is the frequency of a class divided by the total number of measurements.

Accepted Answer

This statement accurately describes the definition of relative frequency.

Question 18

Splitting the stems refers to assigning the same stem to two or more rows of the stem-and-leaf display.

Accepted Answer

Splitting the stems in a stem-and-leaf display means that two or more rows of the display share the same stem. This is a valid technique for reducing the size of the display if there are too many leaves for a given set of data.

Question 19

When we wish to summarize the proportion (or fraction)of items in a class,we use the frequency distribution for each class.

Accepted Answer

The relative frequency summarizes the proportion (or fraction) of items in a class. Frequency distribution shows actual counts of items in each class.

Question 20

A frequency table includes row and column percentages.

Accepted Answer

A frequency table shows the frequency or count of each category, so it only includes row and/or column totals. Percentages may be added separately, but they are not typically included in the standard format of a frequency table.

Quiz 2: Descriptive Statistics: Tabular and Graphical Methods