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 (interquartile range) for the data?

Answer 1

We need to locate the median of the set given. So, it's important for us to arrange the data in increasing order first. Hence we have

10.5 11 11.5 14.5 14.5 17 17 18 19

Now that we have the value of the median for the entire set, we now separate the group into a group below and above the median as shown below.

(10.5 11 11.5 14.5) 14.5 (17 17 18 19)

Now, let's find the median for the subgroup. For the lower boundary, the media is (11 + 11.5)/2 = 11.25. As for the upper boundary, we have (17 + 18)/2 = 17.5.

The interquartile range (IQR) is the difference between the two medians of the lower and upper boundary. Hence, the IQR = 17.5 - 11.25 = 6.25.

Answer: 6.25