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

1 Answer
Jun 30, 2017

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#