Ms. Barnsley separates her class into two groups. She gives each student the same 25-question math quiz. Group A uses a calculator, while Group B does not. The table shows the completion times, in minutes, of students in each group. Quiz Completion Times (minutes) Group A 4 point 5 4 point 6 5 point 0 4 point 8 4 point 4 4 point 7 5 point 2 4 point 6 4 point 8 4 point 9 Group B 5 point 5 4 point 0 4 point 2 4 point 8 4 point 1 3 point 5 3 point 9 4 point 3 4 point 4 4 point 1 Which statement is true about the distributions of completion times?
Answer
A
The standard deviation of Group B is less than the standard deviation of Group A.
B
The means of both groups are about the same.
C
The students in Group A tended to complete the quiz in less time.
D
The median of Group A is greater than the median of Group B.
Explanation
Sort each group’s times and find the middle two values. Group A’s middle values are 4.7 and 4.8 minutes, so its median is (4.7 + 4.8) ÷ 2 = 4.75 minutes. Group B’s middle values are 4.1 and 4.2 minutes, giving a median of 4.15 minutes. Therefore, the median of Group A is greater than the median of Group B.
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