CH 2 Exploring Data With Tables and Graphs

Question 1

What term shows how data are partitioned among several categories (or classes) by listing the categories along with number (frequency) of data values in each of them?

Answer 1

Frequency distribution (Frequency table)

Question 2

In regards to constructing frequency distributions, what term describes the smallest numbers that can belong to each of the different classes?

Answer 2

Lower class limits

Question 3

In regards to constructing frequency distributions, what are the largest numbers that can belong to to each of the different classes?

Answer 3

Upper class limits

Question 4

In regards to constructing frequency distributions, what are the numbers used to separate the classes, but without the gaps created by class limits?

Answer 4

Class boundaries

Question 5

In regards to constructing frequency distributions, what term describes the values in the middle of the classes?

Answer 5

Class midpoints

Question 6

In regards to constructing frequency distributions, what term describes the difference between two consecutive lower class limits in a frequency distribution?

Answer 6

Class width

Question 7

What term describes when each class frequency is replaced by a percentage?

Answer 7

relative frequency distribution

Question 8

How do you calculate the relative frequency for a class?

Answer 8

(frequency for a class) / (Sum of all frequencies)

Question 9

What variation of frequency distribution is used when the frequency of each class is the sum of the frequencies for that class and all previous classes?

Answer 9

cumulative frequency distribution

Question 10

What are some characteristics of approximately normal frequency distribution?

Answer 10

Frequencies start low, then increase to one or two high frequencies, and then decrease to a low frequency
The distribution is approximately symmetric

Question 11

What does the presence of gaps in a frequency distribution suggest?

Answer 11

data are from two or more different populations

Question 12

What term describes a graph consisting of bars of equal width drawn adjacent to each other where the horizontal scale represents classes of quantitative data values and the vertical scale represents frequencies?

Answer 12

histogram

Question 13

List the important uses of a histogram:

Answer 13

Visually displays the shape of the distribution of the data
Shows the location of the center of the data
Shows the spread of the data
Identifies outliers

Question 14

What has the same shape and horizontal scale as a histogram but the vertical scale uses relative frequencies?

Answer 14

Relative frequency histogram

Question 15

What are four common histogram distribution shapes?

Answer 15

Bell shaped
Uniform distribution
Skewed to the right
Skewed to the left

Question 16

What is the criteria for assessing normality with a Normal Quantile Plot?

Answer 16

Normal distribution: pattern is in reasonably close to a straight line and the points do not show some systematic pattern

Question 17

What type of graph consists of quantitative data in which each data value is plotted as a point above a horizontal scale of values?

Answer 17

dotplot

Question 18

What type of graph represents quantitative data by separating each value into two parts: the stem and the leaf?

Answer 18

stempot

Question 19

What type of graph is made of quantitative data that has been collected at different points in time?

Answer 19

Time-series graph

Question 20

What type of graph uses bars of equal width to show frequencies of categories of categorical data?

Answer 20

Bar graphs

Question 21

What is a bar graph with the added stipulation that the bars are arranged in descending order?

Answer 21

Pareto Chart

Question 22

What is a common graph that depicts categorical data as slices of a circle, in which the size of each slice is proportional to the frequency count for the category?

Answer 22

Pie Charts

Question 23

What uses line segments connected to points located directly above class midpoint values?

Answer 23

Frequency Polygon

Question 24

What is a variation of the frequency polygon that uses relative frequencies?

Answer 24

relative frequency polygon

Question 25

What are the advantages of the relative frequency polygon?

Answer 25

two or more can be combined on a single graph for easy comparison

Question 26

List two ways graphs can be deceptive:

Answer 26

Nonzero vertical axis | Pictographs

Question 27

What exists when the values of one variable are somehow associated with the values of the other variable?

Answer 27

correlation

Question 28

What exists between two variables when there is a correlation and the plotted points of paired data result in a pattern that can be approximated by a straight line?

Answer 28

linear correlation

Question 29

What is a plot of paired (x,y) quantitative data with a horizontal x-axis and vertical y-axis?

Answer 29

scatterplot or scatter diagram

Question 30

what is denoted by r, and measures the strength of the linear association between two variables?

Answer 30

linear correlation coefficient

Question 31

What does the computed value of the linear correlation coefficient always fall between?

Answer 31

-1 and 1

Question 32

Regarding linear correlation coefficient, an r value close to what number implies all the data fall exactly on a line?

Answer 32

1 or -1

Question 33

What r value indicates that there is weak or no linear correlation?

Answer 33

if r is close to 0

Question 34

When given a collection of paired sample data, what is the straight line that best fits the scatterplot of the data?

Answer 34

Regression line