Scatterplot graphs help you spot trends by plotting individual data points on a graph with an x-axis and a y-axis. When you place the points, you can often see a pattern in how the two variables move together. In the graph below, the pattern shows a correlation between wingspan and body length in a group of swallows.
Here, the wingspans and body lengths of 31 swallows are plotted on a graph. The x-axis shows each bird’s wingspan, and the y-axis shows each bird’s body length. The points generally rise from left to right, which suggests that birds with larger wingspans tend to have longer bodies.
The graph also includes a couple of outliers (points that don’t fit the overall pattern). For example, one bird with a 21.5 cm body has a wingspan of 40 cm, while another bird with a slightly shorter body (21 cm) has a larger wingspan (41 cm).
A single point on an x/y graph gives you information about two variables: x and y. Bubble graphs build on this idea by replacing each point with a circle (a “bubble”). The size and/or color of the bubble represents additional variables.
A group of middle school students studied the records of seven basketball teams to determine how much height contributes to supremacy on the court. They found that the team with the shortest average height scored fewer points and won fewer games than any other team, and that the tallest team won and scored the most. However, the correlation between height and victory is less clear in teams that are similar in height. Team C is smaller than Team D, for example, but Team C has scored more points even though Team D has won more games. A similar disparity exists between Team E and Team F. Based on these results, the students hypothesized that although height is important, superior skill may ultimately matter more.
Which finding appears both on the chart and in the passage?
a. Team B and Team C won the same number of games, but Team B scored more points.
b. Both Team C and Team E scored more points than Team D and Team F, even though Teams D and F won more games.
c. Team F and Team C won fewer games than Team A and Team B.
d. Team A won only five games, but it scored 90 points overall.
e. Team E won about 65% of its games.
Answer: b. Both Team C and Team E scored more points than Team D and Team F, even though Teams D and F won more games is correct because the graph shows this relationship, and the passage states it directly: “Team C is smaller than Team D, for example, but Team C has scored more points even though Team D has won more games. A similar disparity exists between Team E and Team F.”
a. Team B and Team C won the same number of games, but Team B scored more points is incorrect because Team B won six games, and Team C won seven.
c. Team F and Team C won fewer games than Team A and Team B is incorrect because Teams A and B won the fewest games.
d. Team A won only five games, but it scored 90 points overall is incorrect because Team A scored about 55 points, not 90.
e. Team E won about 65% of its games is incorrect because the total number of games played isn’t given. Without that total, you can’t calculate a win percentage.
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