The reaction time (in seconds) to a stop at a red light for a group of adult men was found to be
0.74, 0.71, 0.41, 0.82, 0.74, 0.85, 0.99, 0.71, 0.57, 0.85, 0.57, 0.55

-What is the first quartile?
A)0.752
B)0.552
C)0.85
D)0.8425
E)0.57

Question

The reaction time (in seconds) to a stop at a red light for a group of adult men was found to be
0.74, 0.71, 0.41, 0.82, 0.74, 0.85, 0.99, 0.71, 0.57, 0.85, 0.57, 0.55

-What is the first quartile?
A)0.752
B)0.552
C)0.85
D)0.8425
E)0.57

Quizplus · Accepted Answer

The first quartile (Q1) is the median of the first half of the data set. When the data is ordered: 0.41, 0.55, 0.57, 0.57, 0.71, 0.71, 0.74, 0.74, 0.82, 0.85, 0.85, 0.99, the first quartile is the average of the third and fourth values: (0.57 + 0.57) / 2 = 0.57.

The Reaction Time (In Seconds) to a Stop at a Red