Question

For Each Data Set, Determine the median, the first and third Quartiles, and the interquartile Range.

Answer 1

1. First of all arrange the data set in either ascending or descending order.
12, 19, 24, 26, 31, 38, 53.  N = 7 (number of data items)
Median position = 1/2(N + 1)th item = 1/2(7 + 1)th item = 1/2(8)th item = 4th item = 26
First quatile = 1/4(N + 1)th item = 1/4(7 + 1)th item = 1/4(8)th item = 2nd item = 19
Third quatile = 3/4(N + 1)th item = 3/4(7 + 1)th item = 3/4(8)th item = 6th item = 38
Interquatile range = Third quartile - first quatile = 38 - 19 = 19