These graphs are used to track trends that appear when you place individual data points on a graph that contains an x-axis and a y-axis. As you can see in the graph below, charting dots in this way reveals a trend–the correlation between wingspan and body length of a group of sparrows.
Here, the wingspan and body lengths of 31 swallows are entered on a chart in which the x-axis represents the birds’ different wingspans, and the y-axis indicates the birds’ varying body lengths. We can see that the birds with the greatest wingspans and longest bodies fly faster than smaller birds with shorter bodies. There are a couple of outliers: a bird with a 21.5 cm body has a wingspan of 40 cm, but a bird with a 21 cm body has a 41 cm wingspan.
Like scatterplot graphs, bubble graphs show the relationships between variables. However, instead of only correlating two variables on an x/y axis, bubble graphs add a third dimension by using bubbles of different colors or sizes to represent a third variable. Bubble graphs are useful for depicting patterns in complex data sets because they present information in a compact format.
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.
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 the statement to be true and because the passage says, “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.”
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.
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.
Team A won only five games, but it scored 90 points overall is incorrect because Team A scored about 55 points, not 90.
Team E won about 65% of its games is incorrect because we have no way of knowing the total number of games played. As a result, we can’t calculate the overall percentage of wins.
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