Question 1

The largest value in a set of data is 160,and the smallest value is 70.If the resulting frequency distribution is to have six classes of equal width,what will be the class interval?
A) 15
B) 6
C) 12
D) 5

Accepted Answer

To find the class interval, subtract the smallest value from the largest value and then divide by the number of classes. (160 - 70) / 6 = 90 / 6 = 15.

Question 2

When some of the variables represent categories,we can apply a useful summarization method called tabulation,where we simply count how many people or items are in each category or combination of categories.

Accepted Answer

This is true. Tabulation, also known as frequency analysis, is a common technique used to summarize categorical data by counting the frequency or number of observations or items in each category.

Question 3

The __________ is a graphical display providing cumulative values for frequencies,relative frequencies,or percentages.
A) stem-and-leaf display
B) dotplot
C) line graph
D) pie chart
E) ogive

Accepted Answer

An ogive is a graph that shows cumulative frequencies, relative frequencies, or percentages. It is also known as a cumulative frequency curve or cumulative distribution function. The other options (stem-and-leaf display, dotplot, line graph, and pie chart) are not typically used to show cumulative values.

Question 4

The class interval is the:
A) number of categories of the frequency distribution.
B) number of data values falling within each class.
C) lower and upper limits of each class.
D) width of each class.
E) mid-point of each class.

Accepted Answer

The class interval is the width of each class, which is determined by the difference between the lower and upper limits. A frequency distribution can have multiple categories, but the class interval specifically refers to the size of each group of data values. The number of data values falling within each class and the mid-point of each class are related to the class interval, but do not define it.

Question 5

The appropriate methods for representing the data do not depend on whether the variable of interest is quantitative or qualitative.

Accepted Answer

The appropriate methods for representing data depend on whether the variable of interest is quantitative or qualitative. Quantitative data is represented using numerical measures such as mean, median, and standard deviation, while qualitative data is represented using charts and graphs such as pie charts and bar graphs.

Question 6

Which of the following techniques are applicable to quantitative data?
A) The data array
B) Frequency distributions
C) Stem-and-leaf display
D) Scatter diagram and Dotplot
E) All of these

Accepted Answer

All of these techniques are applicable to quantitative data. The data array can be used to show the order of the data, frequency distributions can be used to show how often each value appears in the data set, stem-and-leaf displays can be used to show the distribution of the data, and scatter diagrams and dotplots can be used to show the relationship between two variables.

Question 7

To more concisely communicate the information contained,raw data can be visually represented and expressed in terms of statistical summary measures.

Accepted Answer

Visual representations and summary measures help to condense and convey information in a more efficient manner.

Question 8

The following stem-and-leaf output has been generated by Minitab.This data has a negative mode. Stem-and-leaf of $\mathrm { C } 2 \quad \mathrm {~N} = 75$
Leaf Unit $= 0.01$
$\begin{array} { l l l } 1 & - 2 & 6 \ 2 & - 2 & 0 \ 5 & - 1 & 555 \ 8 & - 1 & 420 \ 22 & - 0 & 99999887777665 \ 36 & - 0 & 44322111111000 \ ( 14 ) & 0 & 01122233333344 \ 25 & 0 & 66678889999 \ 14 & 1 & 0022222334 \ 4 & 1 & 56 \ 2 & 2 & 03 \end{array}$

Accepted Answer

A negative mode indicates that the most frequent value is negative. In this stem-and-leaf plot, the leaf values range from -2 to 556, with the most frequent values being -1 and -2. Therefore, the data has a negative mode.

Question 9

The midway point between the upper and lower class limits for a frequency distribution is known as the:
A) class interval.
B) class width.
C) class mark.
D) class frequency.
E) class average.

Accepted Answer

The class mark is the exact middle point between the upper and lower class limits for a frequency distribution. It is also known as the class midpoint or class center. Therefore, choice C is the correct answer. Choices A, B, D, and E are not correct in describing the midway point between the upper and lower class limits.

Question 10

The __________ consists of line segments connecting the points formed by the intersections of the class marks with the class frequencies.
A) frequency polygon
B) histogram
C) stem-and-leaf diagram
D) scatter plot
E) bar graph

Accepted Answer

A frequency polygon is a graph that represents the frequency distribution of a set of data. It is formed by connecting the points created by the intersection of class marks and frequencies with line segments. This creates a polygon-like shape that can be used to analyze and compare data distributions.

Question 11

In a raw data listing,data are listed in increasing or decreasing numerical order.

Accepted Answer

In a raw data listing, data are presented in the order they were collected or received, without being arranged in increasing or decreasing numerical order.

Question 12

A frequency distribution may be converted to show either relative or cumulative frequencies for the data.

Accepted Answer

A frequency distribution can be converted to show both relative frequencies (which indicate proportions or percentages of observations in each category) and cumulative frequencies (which indicate the total number or percent of observations up to a certain category).

Question 13

The simple tabulation and cross-tabulation are tabular methods that can be extended to include the mean or other measures of a selected quantitative variable for persons or items within a category or combination of categories.

Accepted Answer

This statement is true. Simple tabulation and cross-tabulation can be used to include measures of quantitative variables for categories or combinations of categories.

Question 14

Raw data are converted to frequency distributions and visual displays that provide us with a "big picture" of the information collected.

Accepted Answer

Raw data can be easier to interpret when converted into frequency distributions and visual displays such as histograms, bar graphs, and pie charts. These displays provide a summarized view of the data and allow for quick identification of patterns and trends.

Question 15

Compared to the frequency distribution,the stem-and-leaf display provides more detail since it can describe the individual data values as well as show how many are in each group,or stem.

Accepted Answer

The stem-and-leaf display is more detailed than the frequency distribution because it not only indicates how many data points fall within each group or stem but also shows the individual data values within each group.

Question 16

Class limits are the:
A) number of categories of the frequency distribution.
B) number of data values falling within each class.
C) lower and upper boundaries of each class.
D) width of each class.
E) mid-point of each class.

Accepted Answer

Class limits refer to the lower and upper boundaries of each class in a frequency distribution. They are used to determine which data values fall within each class. The other options do not accurately describe class limits. A is incorrect because the number of categories is determined by the analyst and may vary depending on the data. B is incorrect because the number of data values in each class is determined by the frequency of the data values, not the class limits. D is incorrect because the width of each class is determined by the class boundaries, which are the mid-points between the class limits. E is incorrect because the mid-point of each class is not the same as the class limits.

Question 17

A histogram describes a frequency distribution by using a series of adjacent rectangles,each of which has a length that is proportional to the frequency of observations within the range of values it represents.

Accepted Answer

This statement accurately describes a histogram.

Question 18

The set of classes in the frequency distribution should be selected so that any given value falls into at least one category.

Accepted Answer

The answer of The set of classes in the frequency...

Question 19

Contingency tables are used primarily for counts involving qualitative data.

Accepted Answer

Contingency tables are used to organize and analyze counts of two or more variables that have categorical or qualitative data. Therefore, they are primarily used for counts involving qualitative data.

Question 20

The width (class interval)of a frequency distribution class is the difference between the smallest and largest values in a data set.

Accepted Answer

The width (class interval) of a frequency distribution class is the difference between consecutive lower class boundaries or upper class boundaries. It is not necessarily the difference between the smallest and largest values in a data set.

Quiz 2: Visual Description of Data

The largest value in a set of data is 160,and the smallest value is 70.If the resulting frequency distribution is to have six classes of equal width,what will be the class interval?

When some of the variables represent categories,we can apply a useful summarization method called tabulation,where we simply count how many people or items are in each category or combination of categories.

The __________ is a graphical display providing cumulative values for frequencies,relative frequencies,or percentages.

The class interval is the: