The test scores of 19 students are listed below.Find the upper quartile (Q3)by hand. 36 45 49 53 55
56 59 61 62 65
67 71 75 79 82
88 90 92 97
A)55.5
B)82.0
C)65.0
D)79.0
E)80.5

Question

Quizplus · Accepted Answer

To find the upper quartile, we need to first find the median (Q2) of the data set. 
The median is the middle value, so we need to find the average of the two middle values since we have an odd number of data points.
Median (Q2) = (65+67)/2 = 66
Next, we need to find the median of the upper half of the data set. 
There are 9 data points to the right of the median, so we need to find the average of the two middle values in that set. 
The upper half of the data set is: 
67 71 75 79 82 88 90 92 97
Median of Upper Half (Q3) = (82+88)/2 = 85
Therefore, the upper quartile (Q3) is 85. Answer choice B is correct.

The Test Scores of 19 Students Are Listed Below