Question

What is the interquartile range for this set of data? 11, 19, 35, 42, 60, 72, 80, 85, 88

Answer 1

See a solution process below:

(From: http://www.statisticshowto.com/probability-and-statistics/interquartile-range/)

Explanation:

This data set is already sorted. So, first, we need to find the median:

`11, 19, 35, 42, color(red)(60), 72, 80, 85, 88`

Next we put parenthesis around the upper and lower half of the data set:

`(11, 19, 35, 42), color(red)(60), (72, 80, 85, 88)`

Next, we find Q1 and Q3, or in other words, the median of the upper half and lower half of the data set:

`(11, 19,color(red)(|) 35, 42), color(red)(60), (72, 80,color(red)(|) 85, 88)`

`Q1 = (35 + 19)/2 = 54/2 = 27`

`Q3 = (80 + 85)/2 = 165/2 = 82.5`

Now, we subtract `Q1` from `Q3` to find the interquartile range:

`82.5 - 27 = 55.5`