Chapter 2

A relative frequency distribution shows:

the fraction or percentage of observations in each class interval

Suppose a frequency distribution has the following consecutive classes: $20 up to $30 $30 up to $40 $40 up to $50 What is the class midpoint for the first class?

$25

Which of the following is an advantage of a cumulative frequency polygon over a histogram or frequency polygon?

It can show the total number of observations less than a particular class' upper limit.

Which one of the following is not a characteristic of a frequency distribution?

It summarizes qualitative data.

Which of the following practices are commonly used in setting class limits for a frequency distribution?

Rounding the class size up. Placing "excess" interval width equally in the two tails of the distribution.

Which one of the following is true about pie charts?

The size of a slice should represent the relative frequency or percentage.

Which of the following is a feature of a relative frequency distribution?

The sum of the relative frequencies must be one (assuming no rounding errors).

Which of the following are characteristics of frequency tables?

They can be used for qualitative data. No observation can fit into more than one class.

To divide data with a high value of H and a low value of L into k classes, the class interval must be:

at least (H-L)/k

The value shown on the vertical axis of a cumulative frequency polygon for a particular class is found by:

counting the number of observations less than the upper limit of the class

In using the "2 to the k rule" to determine the number of classes for a frequency distribution, what is the meaning of the variable k?

k is the smallest number of classes such that 2k is greater than the number of observations.

A business statistics instructor teaches a class with 83 students. Suppose he would like to create a frequency distribution to summarize their 83 final exam scores. Using the "2 to the k rule," how many classes should used?

7

Which of the following is not a useful practice in setting individual class limits for a frequency distribution?

Excluding outliers that cause the interval to be too wide.

Suppose that the miles per gallon for 80 cars is summarized in a frequency distribution. Below is a part of the distribution. What would the relative frequency be for the class "20 up to 24?"

0.20

Suppose you are trying to summarize a data set with a maximum value of 70 and a minimum value of 1. If you have decided to use seven classes, which one of the following would be a reasonable class interval?

10

Given below are the data for blood types: A B B AB O O O B AB B A B 0 O O A O A A 0 A B B 0 AB Which is the frequency for blood type AB?

3

Which of the following are characteristics of bar charts?

Bar charts are used for qualitative data. Plotted rectangles should be the same width. There should be gaps between bars.

Regarding frequency tables and frequency distributions, which one of the following is true?

Both show the number of observations in each class.

In a frequency polygon the points are plotted at the intersection of the class frequencies and the:

Class midpoints

What is the final step in creating a frequency distribution?

Count the number of observations in each class.

The number of observations in each class is called the class ______.

Frequency

A frequency distribution table shows the number of observations for each class interval of data. How is this data plotted as a frequency polygon?

Frequency is plotted on the vertical axis and the class midpoint is plotted on the horizontal axis.

Which of the following is the best definition of "class midpoint"?

Halfway between the lower or upper limits of two consecutive classes.

Regarding frequency tables and frequency distributions, which of the following are true?

Only frequency tables use qualitative data. Both use mutually exclusive classes.

Which of the following are characteristics of frequency distributions?

Organize raw data It provides the tally for each class. Use classes and frequencies to organize data

Which one of the following is true regarding raw data?

Raw data are simply a listing of data before summarizing it.

Which of the following are characteristics of raw data?

Raw data can be either qualitative or quantitative When the data is in its original form it is referred to as raw data

Which of the following features is not part of a histogram?

The frequency of occurrence of a nominal variable.

A business statistics course has 2 accounting majors, 4 finance majors, 6 marketing majors, and 8 insurance majors. Which one of the following is true if a pie chart was constructed to depict majors of students?

The marketing slice would be three times as big as the accounting slice.

What information is shown on the horizontal axis of a bar chart?

The qualitative class labels.

Which of the following can be observed from a histogram? Check all that apply.

The shape of the distribution. The spread of the data. The approximate number of observations.