Solved Examples and Worksheet for Interpreting Scatter Plots

Q1The scatter plot shown gives the relationship between the demand and price of consumer goods. What trend does the graph follow?

A. Negative trend
B. No trend
C. Positive trend

Step: 1
From the graph, as the demand of an item rises, there is a rise in the price of the item and as the demand reduces there is a decrease in the price of an item.
Step: 2
If one set of data tends to increase with an increase in the other set, the plot is said to have a positive trend.
Step: 3
So, the scatter plot shows a positive trend.
Correct Answer is :   Positive trend
Q2The scatter plot displays Andrew's height over a few years. What was Andrew's height when he was 15 years old?

A. 4 ft
B. 5.6 ft
C. 3.5 ft
D. 5 ft

Step: 1
The vertical coordinate of each point in the scatterplot represents Andrew's height and the horizontal coordinate represents his age.
Step: 2
From the graph, the vertical coordinate of the point corresponding to 15 years is 5 ft.
Step: 3
So, Andrew was 5 ft tall when he was 15 years old.
Correct Answer is :   5 ft
Q3The following scatter plot represents the distance traveled by Diane during each hour of her journey. Find the distance traveled by her in 3 hours.

A. 157.5 km
B. 55 km
C. 52.5 km
D. 160 km

Step: 1
The vertical coordinate of each point on the scatter plot indicates the distance traveled by Diane during each hour.
Step: 2
The distance traveled in the first hour of the journey is 50 km.
Step: 3
The distance traveled in the second hour is 55 km.
Step: 4
The distance covered in third hour is 52.5 km. as it is in between 50 and 55.
Step: 5
The total distance covered in the first three hours of the journey = 50 + 55 + 52.5 = 157.5 km.
Step: 6
The distance traveled by Diane in 3 hours is 157.5 km.
Correct Answer is :   157.5 km
Q4The scatter plot represents the number of items of different costs purchased by Lindsay in a supermarket. What is the total amount spent by her in the supermarket?

A. $50 B.$90
C. $80 D.$100

Step: 1
The height of each point on the scatter plot indicates the number of items of a particular cost bought by Lindsay.
Step: 2
From the graph, the number of items of costs $2,$4, $6,$8 and $10 are 3, 5, 3, 2 and 3 respectively. Step: 3 The total amount spent by her is the sum of the products of the number of items and the cost of each item. Step: 4 So, the total amount =$2 x 3 + $4 x 5 +$6 x 3 + $8 x 2 +$10 x 3
= 6 + 20 + 18 + 16 + 30 = $90 [Multiply number of items and cost of each item and add all.] Step: 5 So, Lindsay spent$90 in the supermarket.
Correct Answer is :   $90 Q5The scatter plot represents the contributions made by a few people to an orphanage in the last 3 years. What is the minimum contribution made to the orphanage? A.$1,000
B. $3,000 C.$2,000
D. $4000 Step: 1 The height of each point in the plot represents the contribution made in that particular year. Step: 2 The height of the point corresponding to the 1st year represents the value$1000, which is the least.
Step: 3
So, the minimum contribution made to the orphanage was $1,000. Correct Answer is :$1,000
Q6The scatter plot represents the distance traveled by Victor at different speeds. How many more miles can he travel if he travels at 80 mph than that when he travels at 70 mph?

A. 65
B. 40
C. 35
D. 90

Step: 1
The height of each point in the scatter plot gives the distance traveled by Victor at the particular speed in the time.
Step: 2
From the graph, Victor can travel 150 miles in the time if he travels at 70 mph.
Step: 3
Victor can travel 190 miles in the time if he travels at 80 mph.
Step: 4
Difference between the distances = 190 - 150 = 40
[Subtract 150 from 190.]
Step: 5
So, Victor can travel 40 more miles in the time if he travels at 80 mph than that when he travels at 70 mph.
Q7The scatter plot shows the population of Alabama and California from 1998 through 2002. By what percent did the population of Alabama increase from 1999 to 2002?

A. 200%
B. 100%
C. 50%
D. 150%

Step: 1
The height of each point in the plot represents the population of a particular state in a particular year.
Step: 2
From the plot, the population of Alabama in the year 1999 is 4 million.
Step: 3
The population of Alabama in the year 2002 is 8 million.
Step: 4
Increase in the population = 8 - 4 = 4 million
[Subtract 4 from 8.]
Step: 5
So, the percentage increase in the population = IncreaseOriginal x 100
= 44 x 100 = 100%
[Divide.]
Q8The scatter plot displays the weight of Charles as he grew older. What was his weight when he was 30 years old?

A. 100
B. 125
C. 50
D. 175

Step: 1
In the scatter plot, the horizontal axis represents Charles's age and the vertical axis represents his weight in lb.
Step: 2
The vertical distance of each point in the scatter plot indicates the weight of Charles when he was a particular age.
Step: 3
From the graph, the vertical distance of the point corresponding to 30 is 125.
Step: 4
So, the weight of Charles was 125 lb when he was 30 years old.
Q9The scatter plot displays the weight of Jeff as he grew in age. At what age was his weight 100 lb.?

A. 10
B. 60
C. 20
D. 30

Step: 1
In the scatter plot, the horizontal axis represents Jeff's age and the vertical axis represents his weight in lb.
Step: 2
The vertical distance of each point in the scatter plot indicates the weight of Jeff when he was a particular age.
Step: 3
From the graph, the vertical distance of the point corresponding to 20 is 100.
Step: 4
So, Jeff's weight was 100 lb. when he was 20 years old.
Q10A wholesale dealer of stationery products plots the following scatter diagram of his income from the year 1985 to 2000. In which year was his income the highest?

A. 2000
B. 1995
C. 1990
D. 1985

Step: 1
The height of each point in the graph indicates the income (in $1000) of the dealer in the corresponding year. Step: 2 From the graph, the incomes of the dealer in 1985, 1990, 1995 and 2000 are$40000, $45000,$35000 and $50000, respectively. Step: 3 The income of the dealer was the highest in 2000. Correct Answer is : 2000 Q11The scatter plot displays the income earned by a wholesale dealer of stationery products from 1985 through 2000. What is his income in the year 2000? A.$35 thousands
B. $40 thousands C.$45 thousands
D. $50 thousands Step: 1 In the scatter plot, the horizontal axis indicates the year and the vertical axis indicates the income (in$1000) earned by the wholesale dealer.
Step: 2
The height of each point in the graph indicates the income (in $1000) of the dealer in the particular year. Step: 3 From the graph, the vertical coordinate of the point corresponding to the year 2000 is 50. Step: 4 So, the income of the wholesale dealer in 2000 was$50,000.
Correct Answer is :   \$50 thousands
Q12The scatter diagram shows the yield of an apple orchard. Find the increase in the number of apples from the year 1985 to 1990.

A. 300
B. 50
C. 200
D. 100

Step: 1
The height of each point in the scatter plot indicates the yield of the apple orchard in the corresponding year.
Step: 2
From the scatter plot, the number of apples in the year 1985 = 700
Step: 3
Number of apples in the year 1990 = 800
Step: 4
Increase in the number of apples
= 800 - 700 = 100
[Subtract.]
Q13What is the ratio of the consumption of goods in 1999 to that in 2000 as seen in the scatter plot?

A. 5 : 7
B. 2 : 3
C. 1 : 1
D. 7 : 5

Step: 1
The vertical coordinate of each point on the scatter plot indicates the consumption of goods (in million tons) in the corresponding year.
Step: 2
From the plot, the consumption of the goods in 1999 was 35 million tons.
Step: 3
The consumption of the goods in the year 2000 is 25 million tons.
Step: 4
So, the ratio of the consumption of goods in 1999 to that in 2000 = 35 : 25 = 7 : 5
Correct Answer is :   7 : 5
Q14The scatter plot shows the number of matches won by teams representing USA from 1986 to 1990. Find the total number of matches won by USA teams from 1988 to 1990.

A. 100
B. 180
C. 250
D. 115

Step: 1
Number of matches won in 1988 = 70
Step: 2
Number of matches won in 1989 = 45
Step: 3
Number of matches won in 1990 = 65
Step: 4
Total number of matches won by USA from 1988 to 1990 = 70 + 45 + 65 = 180
Step: 5
So, the total number of matches won by USA from 1988 to 1990 is 180.
Q15Use the scatter plot and the trend line to estimate the test score of a student who studied for 10 hours.

A. 65
B. 70
C. 72
D. 68
E. 60

Step: 1
Each point in the scatter plot shows the test score of a student who studied for the respective number of hours.
Step: 2
Draw a vertical line starting from 10 hours in the scatter plot. This line intersects the trend line at a point.
Step: 3
From the intersection, draw a horizontal line that intersects the y-axis. This intersection point on the y-axis gives the required test score as the y-axis represents the test scores.
Step: 4
So, a student who studied for 10 hours would have scored about 68 points