Question 1

Ogives are plotted at the midpoints of the class groupings.

Accepted Answer

Ogives are cumulative frequency graphs and are plotted at the upper boundaries of the class intervals, not at the midpoints.

Question 2

The larger the number of observations in a numerical data set, the larger the number of class intervals needed for a grouped frequency distribution.

Accepted Answer

As the number of observations in a data set increases, the range of values also typically increases, requiring more class intervals to effectively group and display the data.

Question 3

The relative frequency is the frequency in each class divided by the total number of observations.

Accepted Answer

This is the definition of relative frequency.

Question 4

A histogram can have gaps between the bars, whereas bar charts cannot have gaps.

Accepted Answer

Both histograms and bar charts can have gaps; however, in histograms, which display frequency distributions for quantitative data, the bars are typically adjacent to each other to emphasize the continuous nature of the data. In contrast, bar charts, which compare discrete categories, often have gaps between bars to distinguish the categories clearly.

Question 5

Apple Computer, Inc.collected information on the age of their customers.Suppose the youngest customer was 12 and the oldest was 72.To study the distribution of the age among its customers, it can use a Pareto chart.

Accepted Answer

A Pareto chart is used to show the relative frequencies of different categories in descending order. It is not appropriate for displaying numerical data, such as age. A histogram or boxplot would be more suitable for displaying the distribution of ages among customers.

Question 6

If you wish to construct a graph of a relative frequency distribution, you would most likely construct an ogive first.

Accepted Answer

To construct a graph of relative frequency distribution, one would typically use a histogram or a relative frequency polygon, not an ogive.

Question 7

An ogive is a cumulative percentage polygon.

Accepted Answer

An ogive is a graph that represents cumulative frequencies or cumulative percentages. It is commonly used in statistics to show the distribution of data. The ogive can be created by plotting the cumulative percentage against the data values and connecting the points with a line.

Question 8

The percentage distribution cannot be constructed from the frequency distribution directly.

Accepted Answer

The percentage distribution can be easily constructed from the frequency distribution by dividing the frequency of each class by the total frequency and multiplying by 100 to obtain the percentage of each class.

Question 9

The stem-and-leaf display is often superior to the frequency distribution in that it maintains the original values for further analysis.

Accepted Answer

The stem-and-leaf display shows the original values and their distribution, which can be helpful in further analysis or calculations. In contrast, the frequency distribution only shows the count or proportion of values falling in each interval, losing some information from the original data set.

Question 10

A side-by-side bar chart is two histograms plotted side-by-side.

Accepted Answer

A side-by-side bar chart consists of two or more sets of bars adjacent to each other to facilitate comparison, while histograms are used to show the distribution of a continuous data set, with bars representing the frequency of data in certain ranges.

Question 11

Histograms are used for numerical data while bar charts are suitable for categorical data.

Accepted Answer

Histograms are used to visually represent distributions in numerical data (such as frequency distributions). Bar charts are used to display data in categorical variables (such as comparing data for different groups or categories).

Question 12

Percentage polygons are plotted at the boundaries of the class groupings.

Accepted Answer

Percentage polygons are plotted at the midpoints of the class intervals, not the boundaries.

Question 13

The original data values cannot be determined once they are grouped into a frequency distribution table.

Accepted Answer

Once the data values are grouped into categories in a frequency distribution table, the original values are lost. Only the frequency or count of values in each category is recorded.

Question 14

A good choice for the number of class groups to use in constructing frequency distribution is to have at least 5 but no more than 15 class groups.

Accepted Answer

Having at least 5 but no more than 15 class groups in constructing frequency distribution ensures that the distribution is not too simplistic (with too few groups) or too complex (with too many groups) and that it effectively represents the data. However, the exact number of class groups needed may also depend on the range and variability of the data.

Question 15

The main principle behind the Pareto chart is the ability to separate the "vital few" from the "trivial many."

Accepted Answer

This is correct; the Pareto chart is used to identify the most significant factors or problems that are causing an issue, allowing the user to focus on addressing those first. It is based on the Pareto principle, also known as the 80/20 rule, which suggests that 80% of the effects come from 20% of the causes.

Question 16

Apple Computer, Inc.collected information on the age of their customers.Suppose the youngest customer was 12 and the oldest was 72.To study the distribution of the age among its customers, it can use a percentage polygon.

Accepted Answer

A percentage polygon is a graph that displays the relative frequency or percentage of observations in each group or category of a dataset. In this case, the age of the customers can be divided into age groups (e.g. 12-20, 21-30, 31-40, etc.) and the percentage of customers in each group can be plotted on a percentage polygon to show the distribution of customer ages.

Question 17

A Walmart store in a small town monitors customer complaints and organizes these complaints into six distinct categories.Over the past year, suppose the company has received 534 complaints.One possible graphical method for representing these data would be a Pareto chart.

Accepted Answer

Pareto charts are used to represent data in the form of a bar graph with the bars arranged in descending order of frequency or size, and the cumulative total of each category is also plotted on the chart. This makes it a suitable graphical method for representing customer complaints organized into distinct categories.

Question 18

Determining the class boundaries of a frequency distribution is highly subjective.

Accepted Answer

Class boundaries can be determined based on the choices and preferences of the person creating the frequency distribution. There is no definitive or objective way to choose the class boundaries.

Question 19

Apple Computer, Inc.collected information on the age of their customers.Suppose the youngest customer was 12 and the oldest was 72.To study the distribution of the age among its customers, it is best to use a pie chart.

Accepted Answer

A pie chart is not the best choice for displaying the distribution of ages among customers as it is difficult to accurately display many categories (such as individual ages) on a pie chart. A histogram or bar graph would be more appropriate for this type of data.

Question 20

Apple Computer, Inc.collected information on the age of their customers.Suppose the youngest customer was 12 and the oldest was 72.To study the percentage of their customers who are below a certain age, it can use an ogive.

Accepted Answer

An ogive is a graph that displays the cumulative frequency of data. In this case, Apple could use an ogive to show the cumulative percentage of their customers who are below a certain age.

Quiz 2: Organizing and Visualizing Variables