Question

sample 2
interpret a scatter plot
roshelle asked 10 friends how many hours of sleep they got the night before
a math test and then matched that data with their math test scores. she plotted the data
in the graph below. did students who slept more get higher test scores?
look at the way the data points are clustered. if the y-values tend to increase as the x-
values increase, there is a positive association. if the y-values tend to decrease as the x-
values tend to decrease as the x-values increase, there is a negative association.
test performance
a cluster is a group of points
that lie close together.
a gap is an area on the graph
that contains no data.
this data point is set off from
the other data points. it is an
outlier.
the scatter plot shows a positive association
between hours of sleep and math test scores.
example 3
construct and interpret a scatter plot
avery is the middle school basketball statistician. she tracks the number of
minutes a player plays and the number of fouls the player makes. her data
are shown in the scatter plot. is there an association between the
number of minutes played and the number of fouls made?
basketball fouls
the y-values do not
increase or decrease
as the x-values increase.
the scatter plot shows no association
between the number of minutes played
and number of fouls made.
try it!
avery also tracks the number of minutes a player plays and the number of
points the player scored. describe the association between the two data
sets. tell what the association suggests.
basketball scoring
4 - 1 construct and interpret scatter plots 321

Explanation:

Step1: Analyze the scatter - plot

In a scatter - plot, if as the \(x\) - values (minutes played) increase, the \(y\) - values (points scored) also increase, we can determine the type of association.
Looking at the Basketball Scoring scatter - plot (the \(x\) - axis is minutes played and the \(y\) - axis is points scored), as the number of minutes played (\(x\)) increases, the number of points scored (\(y\)) increases.

Step2: Identify the association type

When \(y\) - values increase as \(x\) - values increase in a scatter - plot, the association is a positive association. This suggests that, in general, the more minutes a player plays, the more points the player is likely to score.

Answer:

The scatter - plot shows a positive association. This suggests that, on average, as the number of minutes a player plays increases, the number of points the player scores also increases.