 Carrie’s first 4 science test scores were 92, 85, 89 and
90. What score does she need to get on her 5th test in
order to have a mean of 90? Show your work!
92+85+89+90+x = 90
5
92+85+89+90+x = 450
356 + x = 450
x = 94
So far, we have looked at single graphs
and made inferences about one
population. Now we are going to
compare two graphs and make
inferences about two populations.
We will see examples of a:
Double Line Plot
Back-to-back Stem and Leaf Plot
Double Bar Graph/Histogram
Double Box Plot
The double line plot shows the number of minutes
Katie and Danielle trained for a cross-country run.
Which statement is true?
A. Danielle’s times are more spread out.
B. Katie’s times are more spread out.
Which statement is true?
A. Danielle’s times are more consistent.
B. Katie’s times are more consistent.
Find the mean of each line plot.
Who has higher average training time?
A. Katie has the higher average training time.
B. Danielle has the higher average training time.
Katie’s Average Time: 64.9 min
Danielle’s Average Time: 70.8 min
The double histogram shows the heights of the
tallest buildings in Atlanta and Charlotte.
Which statement is true?
A. Atlanta had the tallest building.
B. Charlotte had the tallest building.
Which statement is true?
A. Atlanta has more buildings that are 800-899 ft tall.
B. Charlotte has more buildings that are 800-899 ft
tall.
The back-to-back stem and leaf plot shows the
number of wins of two middle school baseball
teams for the past ten years.
Which statement is true?
A. Westland MS has a more consistent number of wins.
B. Eastland MS has a more consistent number of wins.
Find the median number of wins for each team.
Westland: 24 games
Eastfield: 26 games
The double box plot shows the height (in
inches) of the boys and girls in Ms. Castle’s
class.
Which statement is true?
A. The boys are generally taller.
B. The girls are generally taller.
The double box plot shows the height (in
inches) of the boys and girls in Ms. Castle’s
class.
Which statement is true?
A. 75% of girls are 67 inches or shorter.
B. 75% of boys are 67 inches or shorter.
Find the Inter-quartile Range for girls and boys.
What do you notice? What does this mean?
Girls IQR: 67-64 = 3
Boys IQR: 69-66 = 3
They are the same. This means 50% of the
heights are equally spread out around the
medians.
If there are 16 girls in the class, how many
are 65 inches or taller?
50% of 16 = 8 girls