7.5 Compare and Contrast Graphs
Name _______________________
The following data shows the grams of sugar per serving in 26 cereals made for adults.
0, 0, 0, 0, 0, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 7, 9, 10, 11
1. Use the intervals 0-2, 3-5, 6-8, and 9-11 to make a histogram of the data.
2. 2. Make a circle graph to show the percent of cereals with 0-2, 3-5, 6-8, and 9-11 grams of sugar.
3. Make a line plot of the data
Compare the graphs of one set of data
Type of graph
Advantages
Histogram
Continuous data (time, inches,
temperature) in ordered
columns
Circle Graph
Displays data as % of the whole
Visually appealing
Can analyze big data sets with
wide range
Line Plot
Initial record of discrete (not
continuous) data values.
Quick analysis of data
Shows range, min, max, gaps &
clusters, outliers
Shows exact values
Visually appealing
Shows % of total for each
category
Disadvantages
No exact data
Use only for continuous data
Hard to compare 2 data sets
Reflects normal distribution
No exact data
Total unknown, unless specified
Hard to compare 2 data sets
Best for 3 to 7 categories
Up to 50 data values
Only for small range
Not visually appealing
The following data represents basketball points.
2, 12, 12, 13, 15, 18, 20, 20, 21, 21, 23, 24, 26, 26, 26, 28, 29, 30, 30, 31
4. Make a stem-and-leaf plot
Stem-and-Leaf Plot
Stem and leaf plots record data
values in rows, and can easily be
made into a histogram.
Compact representation of the
ordered data
Shows range, min, max, gaps &
clusters, outliers
Can show extremely large data set.
Not visually appealing
Histograms vs. Bar Graphs
Histograms
Bar Graphs
Use BARS_ to represent the data.
DO NOT have spaces between the bars; the
bars do not touch each other,
to represent the continuous nature of the data.
Divide the data into groups, called “intervals.”
Use _BARS_ to represent that data.
DO have spaces between the bars; the bars
touch each other.
Divide the data in categories.
What is wrong with the given histogram?
(Hint: in which bar will you count the score of 20?)
5. The table shows the time that Mr. O’Brien’s students spent studying and the grade on a test. Make a Scatter plot.
Time Spent
Studying (hours)
1.5
1
3.5
2
2.5
3
1
2
5
As the studying time increases, the
the grades increase
Grade on Test
(%)
84
77
99
91
91
93
83
89
80
Scatter Plot
Displays the relationship between
two data sets and positive, negative
or no correlation.
What relationship shown?
positive
Shows a trend in the data relationship
Retains exact data values
Shows minimum/maximum and outliers
Hard to visualize results in large data sets
Data on both axes should be continuous
Choose the letter that best matches the type of display to its use.
6. Circle Graph _____
a. shows the frequency of data that has been organized into equal intervals
7. Line Graph
_____
b. lists all individual numerical data in a condensed form
8. Bar Graph
_____
c. shows the number of items in specific categories in the data using bars
9. Histogram
_____
d. compares part to a whole
10. Line Plot
_____
e. shows change over a period of time
11. Stem-and-Leaf Plot _____
f. shows how many times each number occurs in the data
Select an appropriate type of display for each situation. Justify your reasoning.
12. energy usage in your home for the past year, categorized by month _____________________
13. exam scores for a whole class, arranged in intervals ____________________
14. sales of a leading brand of toothpaste for the last 10 years ___________________
15. average weight of a pet dog, categorized by breed ___________________
16. runs scored by individual members of a baseball team, as compared to the team total ____________________
17. ages of all 40 employees of a small company ________________________
For Exercises 1–4, use the following information. Cosmic, Inc. is a software company with 30 employees. The ages of
the employees are displayed below using both a histogram and a stem-and-leaf plot.
18. Can you tell from the stem-and-leaf plot how many
employees are between the ages of 20 and 29? If so,
how many are there? Was it easy to find the answer?
19. Can you tell from the histogram how many
employees are between the ages of 30 and 39? If so,
how many are there? Was it easy to find the answer?
20. Can you tell from the stem-and-leaf plot how many
employees are between the ages of 36 and 43? If so,
how many are there? If not, explain your reasoning.
21. Can you tell from the histogram how many
employees are between the ages of 36 and 43? If so,
how many are there? If not, explain your reasoning.