Question

The data shows the number of grams of fat found in 9 different health bars.

11, 11.5, 10.5, 17, 14.5, 14.5, 18, 17, 19

What is the IQR for the data?

Answer choices:
6.25
7
14.5
17.5

Please don't guess, show your work. I really don't understand

Answer 1

IQR is the difference between Q3 and Q1 so we first need to find those values.
The data in order is:
Lower half: 10.5, 11, 11.5, 14.5,
Median (Q2) 14.5,
Upper Half: 17, 17, 18, 19
Since both the upper and lower halves have an even number of data values we need to find the average between the two middle numbers.
Q1 (11 + 11.5)/2 = 11.25
Q3 (17 + 18)/2 = 17.5
IQR = Q3 - Q1 = 17.5 - 11.25 = 6.25