Gr 8 Math: Data – Scatter Plots
1.
What can be concluded from the scatter plot above?
A. The older a person gets, the more television he or she watches.
B. As a person gets older, their taste in television shows changes.
C. The older a person gets, the less television he or she watches.
D. There is no relationship between age and television watching.
Best-Fit Linear Models
2. The graph below shows a line of best fit for data collected on the amount customers spent on a
file sharing service in relation to the amount they uploaded.
The equation of the line of best fit is shown below.
What does the y-intercept represent?
the cost per Mb uploaded
A.
B.
C.
D.
the cost per file uploaded
the cost to enroll in the file sharing service
the cost to upload an unlimited amount of files
Best-Fit Linear Models
3. The scatter plot and a line of best fit show the relationship between the number of pet shelter
TV ads and the number of pets adopted.
Which statement describes the relationship between the number of pet shelter TV ads and the
number of pets adopted?
For every five pet shelter ads shown on the television, six pets were adopted.
A.
B.
C.
D.
There were eight animals adopted from the pet shelter.
For every five pet shelter ads shown on the television, three pets were adopted.
The number of pets adopted decreased with an increase of pet shelter ads on the television.
Two-Way Tables
4. A group of men and women answered a survey asking about the type of weekend activities
they enjoy. The two-way table below shows the data collected.
Men
Yard Work
47
Shopping
10
Watching TV
43
Total
100
Women
18
55
27
100
Total
65
65
70
200
Which correlation does the two-way table suggest?
A.
B.
C.
D.
Men are more likely to enjoy watching television.
Women are less likely to enjoy watching television.
Women are more likely to enjoy yard work.
Men are less likely to enjoy shopping.
Two-Way Tables
5. Students took a poll that asked whether or not they watch television in the evenings and
whether or not they have homework on those same evenings. The two-way table below shows
the results of the poll.
TV
Homework
6
No Homework
12
Total
18
No TV
9
3
12
Total
15
15
30
Which correlation does the two-way table suggest?
A.
B.
C.
D.
Students who watch television in the evenings tend not to have any homework.
Students who watch television in the evenings tend to have homework.
None of the correlations listed are correct.
Students who do not watch television in the evenings tend not to have any homework.
Scatter Plots
6. Which of the following best describes X on the scatter plot below?
A. negative association
B. cluster
C. nonlinear association
D. outlier
Best-Fit Linear Models
7. The scatter plot and a line of best fit show the relationship between the number of traffic
accidents and the number of hours of rainfall during several spring storms.
Which statement describes the relationship between the number of traffic accidents and the
number of hours of rainfall?
A.
B.
C.
D.
During several spring storms, it rained for six hours.
During several spring storms, there were five traffic accidents for every eight hours of rain.
During several spring storms, the longer it rained, the fewer accidents happened.
During several spring storms, there were five traffic accidents.
Two-Way Tables
8. A company is releasing a new line of outlet and countertop air fresheners. The scents in the
new line are Tropical Sunset, Island Coconut, and Vanilla Breeze. The company performed a
market research study with 250 participants and recorded how many participants in the study
preferred each type of air freshener.
Based on the data collected, the company concluded that the majority of customers will prefer
their Island Coconut-scented countertop air freshener.
Which two-way table is a possible representation of the data they collected?
W.
X.
Y.
Z.
A. W
B. Y
C. X
D. Z
Two-Way Tables
9. A movie rental company polled several of their customers to find whether or not they owned a
DVD player or a VCR.
The results of the poll are shown below.




11 customers own both a DVD player and a VCR
12 customers own neither a DVD player nor a VCR
3 customers own only a VCR
49 customers own only a DVD player
Which two-way table represents the results of the poll?
A. X
B. Y
C. Z
D. W
W.
X.
Y.
Z.
Scatter Plots
10. The table below shows the attendance at football games. Which scatter plot matches the
table?
Week Attendance
A. Z
B. W
C. X
D. Y
1
150
2
170
3
190
4
250
5
300
6
290
7
330
8
350
W.
X.
Y.
Z.
Best-Fit Linear Models
11. Which of the scatter plots below shows the most accurate line of best fit?
A. X
B. Y
C. Z
D. W
W.
X.
Y.
Z.
Scatter Plots
12. At a children's archery camp, the percentage of target hits at different distances from the
target for several students were recorded. The data is shown in the scatter plot below.
Which of the following can be interpreted from this data?
There is no association between the distance from the target and the percentage of target
A. hits.
There is a positive association between the distance from the target and the percentage of
B. target hits.
There is a negative association between the distance from the target and the percentage of
C. target hits.
There is both a positive and a negative association between the distance from the target
D. and the percentage of target hits.
Two-Way Tables
13. A travel agent collected data from a group of past clients regarding what type of reservation
they plan to make in the future and which package they plan to choose. The types of reservations
offered at the agency are tours, cruises, and resorts, and the packages offered are either basic or
deluxe.
The two-way table below displays the relative frequencies of the data.
Tours Cruises Resorts
Total
Basic
0.10
0.15
0.25
0.50
Deluxe
0.20
0.08
0.22
0.50
Total
0.30
0.23
0.47
1.00
Based on the relative frequencies of the table, which two-way table is a possible representation
of the data collected?
A. Z
B. X
C. W
D. Y
Scatter Plots
W.
X.
Y.
Z.
14. At an amusement park, a lemonade stand was next to a roller coaster.
Throughout the day, people who got off the ride and purchased lemonade were asked how long
they had to wait in line for the roller coaster. The results are shown in the scatter plot below.
Which statement is supported by the data in the scatter plot?
As the wait time increases, the number of cups of lemonade sold tends to decrease.
A.
B.
C.
D.
As the wait time increases, the number of cups of lemonade sold tends to increase.
There is no relationship between the wait time and the number of cups of lemonade sold.
As the wait time increases, the number of cups of lemonade sold tends to stay the same.
Best-Fit Linear Models
15. Which of the scatter plots below shows the most accurate line of best fit?
W.
X.
Y.
Z.
A. X
B. Z
C. W
D. Y
Answers
1. C
2. C
3. C
4. D
5. A
6. B
7. B
8. D
9. D
10. C
11. D
12. C
13. D
14. C
15. A
Explanations
1. Age is shown on the x-axis. Amount of time spent watching television is on the y-axis. As the
numbers increase on the x-axis, the numbers decrease on the y-axis.
Therefore, it can interpreted from the scatter plot that the older a person gets, the less television
he or she watches.
2. The y-intercept is the value of the quantity on the y-axis when the quantity on the x-axis is
zero.
In this case, the quantity on the x-axis is the amount uploaded. When this is zero, the customer
has subscribed to the file sharing service but has not uploaded any files.
Therefore, the y-intercept is the cost to enroll in the file sharing service.
3. Locate two points on the line to determine the relationship between the number of pet shelter
TV ads and the number of pets adopted.
Two identifiable points from the line of best fit are (0, 3) and (5, 6). Subtract the coordinates of
the left point from the coordinates of the right point.
Pets Adopted: 6 pets - 3 pets = 3 pets
TV Ads: 5 ads - 0 ads = 5 ads
Since the number of pet shelter TV ads is positive, for every five shelter ads shown on the
television, three pets were adopted.
4. Calculate the relative frequency of the rows.
Yard Work
Shopping
Watching
TV
Total
Men
0.47
0.10
0.43
1.00
Women
0.18
0.55
0.27
1.00
Total
0.33
0.33
0.35
1.00
*Note: Values in the table are rounded to the nearest hundredth.
Of the men, 47% enjoy yard work, 10% enjoy shopping, and 43% enjoy watching television.
So, men are less likely to enjoy shopping and more likely to enjoy yard work.
Of the women, 18% enjoy yard work, 55% enjoy shopping, and 27% enjoy watching television.
So, women are less likely to enjoy yard work and more likely to enjoy shopping.
Of the given correlations, men are less likely to enjoy shopping is the correlation suggested by
the two-way table.
5. Calculate the relative frequency of the rows.
TV
0.33
No
Homework
0.67
No TV
0.75
0.25
1.00
Total
0.50
0.50
1.00
Homework
Total
1.00
*Note: Values in the table are rounded to the nearest hundredth.
Of the students who watch television, 33% have homework, and 67% do not have homework.
So, students who watch television in the evening tend not to have homework.
Of the students who do not watch television, 75% have homework, and 25% do not have
homework.
So, students who do not watch television in the evenings tend to have homework.
Of the given correlations, students who watch television in the evenings tend not to have any
homework is the correlation suggested by the two-way table.
6. A cluster is data that are grouped closely together.
In this case, X is close to several data points that are grouped closely together.
Therefore, X is best described as a cluster.
7. Locate two points on the line to determine the relationship between the number of traffic
accidents and the number of hours of rainfall during several spring storms.
Two identifiable points from the line of best fit are (0, 0) and (8, 5). Subtract the coordinates of
the left point from the coordinates of the right point.
Hours of Rainfall: 8 hours - 0 hours = 8 hours
Traffic Accidents: 5 accidents - 0 accidents = 5 accidents
Therefore, during several spring storms, there were five traffic accidents for every eight
hours of rain.
8. Since 250 people participated in the market research study, the values in the two-way table
must total 250.
Therefore, table X can be eliminated because the values in the table total 254.
The company concluded that the majority of customers will prefer their Island Coconut-scented
countertop air freshener.
Therefore, the largest number of participants must be in the "Countertop" column and the "Island
Coconut" row.
Table Z has the largest number of participants (83) in this cell.
Therefore, table Z is a possible representation of this information.
9. The table that represents the results of the poll must have the following attributes.

the number 11 in the "DVD" column and the "VCR" row

the number 12 in the "No DVD" column and the "No VCR" row

the number 3 in the "No DVD" column and the "VCR" row

the number 49 in the "DVD" column and the "No VCR" row
Therefore, table W represents the results of the poll.
10. To determine which scatter plot matches the table, choose any of the points from the table
and plot them on the graphs. The Week will be the x-value and the Attendance will be the yvalue.
For example, choose the points (1, 150), (2, 170), (3, 190), and (4, 250).
The only scatter plot that contains these points is X.
11. The line of best fit is the line that most accurately approximates the data on a scatter plot.
The line may pass through some or none of the points.
The line graph that shows the most accurate line of best fit is W.
12. Distance from the target (in feet) is shown on the horizontal axis. Percentage of target hits is
shown on the vertical axis. As the distance from the target increased, the percentage of target hits
decreased.
The dots on the scatter plot go down and to the right. This indicates a negative association.
Therefore, there is a negative association between the distance from the target and the
percentage of target hits.
13. The correct table must display the following information.






10% plan to make a basic tour reservation
20% plan to make a deluxe tour reservation
15% plan to make a basic cruise reservation
8% plan to make a deluxe cruise reservation
25% plan to make a basic resort reservation
22% plan to make a deluxe resort reservation
To find the relative frequencies in each table, divide each number by the total number of clients
in the table.
The only table which is a possible representation of the data collected is table Y.
Tours
Cruises
Resorts
Total
Basic
20 ÷ 200 = 0.10
30 ÷ 200 = 0.15
50 ÷ 200 = 0.25
100 ÷ 200 = 0.50
Deluxe
40 ÷ 200 = 0.20
16 ÷ 200 = 0.08
44 ÷ 200 = 0.22
100 ÷ 200 = 0.50
Total
60 ÷ 200 = 0.30
46 ÷ 200 = 0.23
94 ÷ 200 = 0.47
200 ÷ 200 = 1.00
14. The length of the wait time is shown on the x-axis. The number of cups of lemonade is
shown on the y-axis.
There is no trend in this graph. The dots do not appear to make a line in one direction or another.
Therefore, there is no relationship between the wait time and the number of cups of
lemonade sold.
15. The line of best fit is the line that most accurately approximates the data on a scatter plot.
The line may pass through some or none of the points.
The line graph that shows the most accurate line of best fit is X.