An interquartile range is finding the median of the first half of the data set, and the second half, then subtracting the first median from the second one.
The median of the data set is..
17, 18, 18, 20, 23, 25, 27, 27, 34, 38, 40, 46, 46, 62, 67
Now we have to find the interquartile points.
17, 18, 18, 20, 23, 25, 27, 27, 34, 38, 40, 46, 46, 62, 67
The interquartile points are 20 and 46. So subtract:
46 - 20 = 26
The answer is 26. :)
Hopefully this helps! If you have any more questions or don't understand, feel free to DM me, and I'll get back to you ASAP! :)