Deck 2: Visual Description of Data

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

Answer 1

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.

Answer 2

True

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

Answer 3

ogive

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.

Question 5

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

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

Question 7

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

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 $= 0.01$
$\begin{array} { l l l } 1 & - 2 & 6 \\ 2 & - 2 & 0 \\ 5 & - 1 & 555 \\ 8 & - 1 & 420 \\ 22 & - 0 & 99999887777665 \\ 36 & - 0 & 44322111111000 \\ ( 14 ) & 0 & 01122233333344 \\ 25 & 0 & 66678889999 \\ 14 & 1 & 0022222334 \\ 4 & 1 & 56 \\ 2 & 2 & 03 \end{array}$

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.

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

Question 11

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

Question 12

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

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.

Question 14

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

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.

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.

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.

Question 18

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

Question 19

Contingency tables are used primarily 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.

Question 21

A cumulative frequency distribution lists the number of observations that are within or ____________________ each of the classes.

Question 22

A stem-and-leaf display describes two-digit integers between 20 and 80.For one of the classes displayed,the row appears as 5|246.What numerical values are being described?

A) 25,45,and 65
B) 60,50,40,and 20
C) 52,54,and 56
D) 46 and 52

Question 23

The cumulative frequency distribution describes the

A) number of observations that fall within each class.
B) proportion of observations that fall within each class.
C) number of observations that are within or below each of the classes.
D) proportion of observations that are within or below each of the classes.
E) None of these is correct.

Question 24

The relative frequency distribution describes the

A) number of observations that fall within each class.
B) proportion of observations that fall within each class.
C) number of observations that are within or below each of the classes.
D) proportion of observations that are within or below each of the classes.
E) None of these is correct.

Question 25

____________________ is also known as marginal or one-way tabulation.

Question 26

The ____________________ is a diagram in which each point represents a pair of known or observed values of two variables.

Question 27

A frequency distribution is a(n):

A) table of the individual observations collected from a sample.
B) individual listing of the random values found in a data set.
C) listing of the individual observations arranged in ascending or descending order.
D) table,which classifies the number of data values into classes.

Question 28

The following stem-and-leaf output has been generated by Minitab. How many values are positive?

Question 29

Which of the following is not a guideline for constructing a frequency distribution?

A) If possible,open-end classes should be avoided.
B) The set of classes must be mutually exclusive and exhaustive.
C) Whenever possible,the classes should have equal width.
D) Whenever possible,class widths should be round numbers.
E) All of these are guidelines for constructing a frequency distribution.

Question 30

The ____________________ describes a frequency distribution by using a series of adjacent rectangles with no gaps in-between,each of which has the length that is proportional to the frequency of the observations within the range of values it represents.

Question 31

The difference between a histogram and a bar chart is that:

A) the histogram reflects qualitative data while the bar chart represents quantitative data.
B) the adjacent rectangles in a histogram have a gap while those for a bar chart do not.
C) the histogram reflects quantitative data while the bar chart represents qualitative data.
D) the adjacent rectangles in a bar chart have a gap while those for a histogram usually do not.
E) Both answers C and D are correct.

Question 32

The ____________________ is also known as the contingency table.

Question 33

In a __________,we can generate a display that describes how a selected qualitative variable tends to differ from one category to another.

A) histogram
B) crosstab
C) relative frequency distribution
D) pie chart
E) line graph

Question 34

A relative frequency distribution describes the____________________ or ____________________ of data values that fall within each category.

Question 35

The grades on a chemistry exam for a sample of 40 students are as follows: Estimate the percentage of grades that are between 80 and 90.

Question 36

In cross-tabulation:

A) data are represented in a table showing how many people or items are in combinations of categories.
B) we can identify possible relationships between the variables.
C) data are represented as a circular display divided into sections based on the number of observations within the segments.
D) data are represented as a pair of known values of two variables,one being referred to as independent and the other,dependent.
E) Both A and B are correct.

Question 37

In a scatter diagram,data are represented as:

A) dots which allow us to readily see the shape of the distribution as well as the high and low values.
B) frequencies according to the relative length of a set of rectangles.
C) a subset of the original digits as class descriptors.
D) a circular display divided into sections based on the number of observations within the segments.
E) pairs of known values of two variables,one being referred to as independent and the other,dependent.

Question 38

In the stem-and-leaf display,data are represented as:

A) dots which allow us to readily see the shape of the distribution as well as the high and low values.
B) frequencies according to the relative length of a set of rectangles.
C) a subset of the original digits as class descriptors.
D) a circular display divided into sections based on the number of observations within the segments.
E) pairs of known values of two variables,one being referred to as independent and the other,dependent.

Question 39

The following stem-and-leaf output has been generated by Minitab. Stem-and-leaf of C2 $\quad \mathrm { N } = 10$
Leaf Unit $= 0.10$
$\begin{array} { l c } 2 & - 153 \\ 4 & - 097 \\ ( 2 ) & - 065 \\ 4 & 03 \\ 3 & 06 \\ 2 & 13 \\ 1 & 18 \end{array}$ Which of the following statements are correct?

A) This data set has a mean that is negative.
B) This data set has a median less than -0.5
C) There is no modal class
D) This data set has six negative values
E) All of these are correct

Question 40

A requirement for a frequency distribution is that the set of classes must be mutually exclusive.This means that

A) the set of classes must include all possible data values.
B) a given data value can fall into only one class.
C) the classes must have equal widths.
D) classes must have an upper limit.
E) classes must have a lower limit.

Question 41

Voters participating in a recent election exit poll in Michigan were asked to state their political party affiliation.Coding the data 1 for Republican,2 for Democrat and 3 for Independent,the data collected were as follows: 3,2,3,2,1,1,3,2,1,3,1,2,3,1,3,3,3,3,2,1,1,3,2,3,1
Construct a frequency bar chart.

Question 42

The ages for a sample of 25 car dealers are as follows:
Use Minitab to draw each of the following graphs.
a.A stem and leaf plot
b.a dot plot

Question 43

What is the difference between a histogram and a bar chart? For what type of data would each be appropriate?

Question 44

Voters participating in a recent election exit poll in Michigan were asked to state their political party affiliation.Coding the data 1 for Democrat,2 for Republican and 3 for Independent,the data collected were as follows: 1,1,2,3,1,2,3,2,1,2,3,2,1,1,3,2,1,1,1,2,3,2,1,1,3
Develop a frequency distribution and proportion distribution for the data.What does the data suggest about the strength of the political parties in Michigan?

Question 45

Discuss the importance of choosing a symbol for a pictogram.

Question 46

Discuss the guidelines that are recommended for constructing a frequency distribution.

Question 47

A medical statistician wanted to examine the relationship between the amount of sunshine (x)and incidence of skin cancer (y).As an experiment he found the number of skin cancers detected per 100,000 of population and the average daily sunshine in eight counties around the country.These data are shown below. Draw a scatter plot and find the least squares regression line. ____________________

Question 48

A physician takes the following sample of blood cholesterol levels form a group of volunteers (one reading per volunteer): 221,202,216,227,232,218,225,234,203,247.
a.In what form,if any are these data organized?
b.Construct a frequency distribution,with class intervals of 10 points for these results.

Question 49

The grades on a statistics exam for a sample of 40 students are as follows:
Construct frequency and relative frequency distributions for the data using seven class intervals.

Question 50

A grocery store's monthly sales (in thousands of dollars)for the last year was as follows:
Construct a line graph for these data.

Question 51

A recent Wall Street Journal poll asked a sample of professional,white collar,and blue-collar workers whether they felt legal immigration had a positive effect on the United States.The responses were graphed as follows: Identify the type of chart shown,and describe the information it gives.

Question 52

The ____________________ a variant of the frequency distribution,uses a subset of the original digits in the raw data as class descriptors and class members.

Question 53

A friend has constructed the following frequency distribution of test scores in his business statistics class:
He asks for your feedback.What advice would you give him?

Question 54

The following table represents exam grades from 36 students in a statistics class.Construct a pie chart using classes with grades 51-60,61-70,71-80,81-90,and 91-100.

Question 55

The following table represents exam grades from 36 students in a statistics class.Construct a stem-and-leaf display.

Question 56

What is a scatter diagram,and for what kind of data is it a useful descriptive device?

Question 57

What is the relationship between a frequency distribution and a histogram?

Question 58

The ages of a sample of 25 salespersons are as follows:
Use Excel or Minitab to draw a histogram with five classes.

Question 59

The general manager of a chain of furniture stores believes that experience is the most important factor in determining the level of success of a salesperson.To examine this belief she records last month's sales (in $1,000s)and the years of experience of 10 randomly selected salespeople.These data are listed below. Draw a scatter diagram of the data and determine the least squares regression line.

Question 60

Consider the following cumulative frequency distribution.
Find the frequencies for each of the following classes:
a.0 - under 5
b.5 - under 10
c.10 - under 15
d.15 - under 20
e.20 - under 25

Question 61

Differentiate between a positive linear relationship and a negative linear relationship between variables.

Question 62

Define and give a real or hypothetical example of simple tabulation.

Question 63

A professor of economics wants to study the relationship between income and education.A sample of 10 individuals is selected at random,and their income (in thousand of dollars)and education (in years)are shown below: Draw a scatter diagram for these data with the income on the vertical axis.Describe the relationship between income and education.

Question 64

A recent Wall Street Journal survey found that 523 Democrats and 765 Republicans and believe legal immigration has a positive effect on the Untied States.Display this data in a bar chart.

Question 65

The general manager of a chain of furniture stores believes that experience is the most important factor in determining the level of success of a salesperson.To examine this belief she records last month's sales (in $1,000s)and the years of experience of 10 randomly selected salespeople.These data are listed below. Interpret the value of the slope of the regression line.

Question 66

Define and give a real or hypothetical example of cross-tabulation.

Question 67

When variables are used as the basis for a cross-tabulation,what scale of measurement must they represent?