Statistics Chapter 2

Refer to the following information from a frequency distribution for "heights of college women" recorded to the nearest inch: the first two class midpoints are 62.5" and 65.5". What are the class limits for the lowest class?

61 and up to 64

Refer to the following information from a frequency distribution for "heights of college women" recorded to the nearest inch: the first two class midpoints are 62.5" and 65.5". What are the class limits for the third class?

67 and up to 70

If the number of observations is 124, calculate the suggested number of classes using the "2 to the k rule."

7 x classes

A _____ chart is useful for displaying a frequency distribution for a nominal variable.

Bar

A _____ chart is useful for displaying a frequency distribution for a qualitative variable.

Bar

The number of observations in each class of a frequency distribution is called a ________________________.

Class frequency or frequency

For a frequency distribution of quantitative data, if every individual, object, or measurement can be assigned to a class, the frequency distribution is __________.

Exhaustive

To convert a frequency distribution to a relative frequency distribution, divide each class frequency by the number of classes.

False

To summarize the gender of students attending a college, the number of classes in a frequency distribution depends on the number of students.

False

In a frequency distribution, the number of observations in a class is called the class ________.

Frequency

What is the following table called?

Frequency distribution

The midpoint of a class interval is also called a class ________.

Mark

A class relative frequency represents a __________ of the total observations in the class.

Proportion or percentage

A student was studying the political party preferences of a university's student population. The survey instrument asked students to identify themselves as a Democrat or a Republican. This question is flawed because:

The categories are not exhaustive

For a relative frequency distribution, relative frequency is computed as _____________.

The class frequency divided by the total frequency

A student was interested in the cigarette smoking habits of college students and collected data from an unbiased random sample of students. The data is summarized in the following table.

The classes are not mutually exclusive

To calculate a relative frequency, a class frequency is divided by ___________.

The total number of observations

A frequency distribution groups data into classes showing the number of observations in each class.

True

A frequency polygon is a very useful graphic technique when comparing two or more distributions.

True

In frequency distributions, classes are mutually exclusive if each individual, object, or measurement is included in only one category.

True

To construct a pie chart, relative class frequencies are used to graph the "slices" of the pie.

True

The monthly salaries of a sample of 100 employees were rounded to the nearest $10. They ranged from a low of $1,040 to a high of $1,720. If we want to condense the data into seven classes, what is the most convenient class interval?

$100 ($1720 - 1040)/7 = $97.14. Of the answer choices, a class interval of $100 is closest to 97.14)

In constructing a frequency distribution, the approximate class width is computed as

(maximum value-minimum value)(sample size)

In a relative frequency distribution, the sum of the relative class frequencies is _____________________.

1.00

A group of 100 students were surveyed about their interest in a new Economics major. Interest was measured in terms of high, medium, or low. In the study, 30 students responded high interest, 50 students responded medium interest, and 20 students responded low interest. What is the best way to illustrate the relative frequency of student interest?

Use a pie chart

When data is collected using a qualitative, nominal variable (in other words, male or female), what is true about a frequency distribution that summarizes the data?

The number of classes corresponds to the number of a variables values

A pie chart is similar to a relative frequency distribution.

True

A pie chart shows the relative frequency in each class.

True

In a bar chart, the heights of the bars represent the frequencies in each class.

True

In a bar chart, the x-axis is labeled with the values of a qualitative variable.

True

The midpoint of a class, which is also called a class mark, is halfway between the lower and upper limits.

True

To convert a frequency distribution to a relative frequency distribution, divide each class frequency by the sum of the class frequencies.

True

To summarize the gender of students attending a college in a frequency distribution, a total of at least ______ classes would be required.

Two

When data is collected using a quantitative, ratio variable, what is true about a frequency distribution that summarizes the data?

Upper and lower class limits must be calculated

In a cumulative frequency distribution, the percent of the total frequencies that would fall below the upper limit of the highest class would be _________.

100%

A student was interested in the cigarette smoking habits of college students and collected data from an unbiased random sample of students. The data is summarized in the following table:

Bar chart

A frequency distribution for nominal data requires that the categories be ___________________ and _____________________.

Exhaustive; mutually exclusive

A frequency distribution for qualitative data has class limits.

False

When classes in a frequency table are constructed so that each observation will fit into only one class, the categories are ______________________.

Mutually Exclusive

When a class interval is expressed as 100 up to 200, _________________________.

Observations with values of 200 are excluded from the class

The relative frequency for a class represents the ________________.

Percent of observations in the class

A ______ chart is useful for displaying a relative frequency distribution.

Pie

A ___________ is useful for displaying the relative frequency distribution for a nominal variable.

Pie chart

A pie chart shows the ______________________.

Relative frequencies of a qualitative variable

A table summarizing a set of data showing the fraction of the total number of items in several classes is a

Relative frequency distribution

Why are unequal class intervals sometimes used in a frequency distribution?

To avoid a large number of empty classes

A class interval, or class width, can be determined by subtracting the lower limit of a class from the lower limit of the next higher class.

True

A cumulative frequency distribution is used when we want to determine how many observations lie above or below certain values.

True

To construct a histogram, the class frequencies are plotted on the ________.

Y or vertical axis

For a frequency distribution of qualitative data, if the observations can be assigned to only one class, the classes are __________________________.

Mutually exclusive

In constructing a frequency polygon, class frequencies are scaled on the ______ axis.

Y or vertical

To construct a bar chart, the class frequencies are plotted on the _________.

Y or vertical axis

When data is collected using a qualitative, nominal variable, what is true about a frequency distribution that summarizes the data?

A pie chart can be used to summarize the data

In a deck of cards, a class of all cards that are hearts and a class of all cards that are kings are NOT _____________.

Mutually exclusive

In a frequency distribution, a class defined as "Under $100" and "$1,000 and over" is called a(n) ____________.

Open class

A group of 100 students was surveyed about their interest in a new International Studies program. Interest was measured in terms of high, medium, or low. In the study, 30 students responded high interest, 40 students responded medium interest, and 30 students responded low interest. What is the relative frequency of students with high interest?

.30

The suggested class interval for a frequency distribution with data ranges from 100 to 220 with 50 observations would be _______.

20

Refer to the following information from a frequency distribution for "heights of college women" recorded to the nearest inch: the first two class midpoints are 62.5" and 65.5". What is the class interval?

3

A student was interested in the cigarette smoking habits of college students and collected data from an unbiased random sample of students. The data is summarized in the following table:

Pie chart

A small sample of computer operators shows monthly incomes of $1,950, $1,775, $2,060, $1,840, $1,795, $1,890, $1,925, and $1,810. What are these ungrouped numbers called?

Raw data

A student was studying the political party preferences of a university's student population. The survey instrument asked students to identify their political preference, for example, Democrat, Republican, Libertarian, or another party. The best way to illustrate the frequencies for each political preference is a __________.

Bar chart

A table showing the number of observations that have been grouped into each of several classes is called a frequency ________________.

Distribution

In order to convert class frequency to relative class frequency, we

Divide the frequency of the class by the sample size

A student was studying the political party preferences of a university's student population. The survey instrument asked students to identify their political preference—for example, Democrat, Republican, Libertarian, or another party. The best way to illustrate the relative frequency distribution is a __________.

Pie chart

Monthly commissions of first-year insurance brokers are $1,270, $1,310, $1,680, $1,380, $1,410, $1,570, $1,180 and $1,420. These figures are referred to as a(n) __________.

Raw data

Unorganized data is referred to as ________ data.

Raw or ungrouped

To construct a pie chart, the class frequencies are converted to __________.

Relative frequencies