You will notice that the fact there is an outlier in this data (60 ... range is the difference between the upper quartile and lower quartile. Interquartile range = upper quartile - lower quartile ...

To find the lower quartile or the value that is one quarter of the way along the list, count how many numbers there are, add 1 and divide by 4. Lower quartile = \(\frac{7 + 1}{4}\) ...