The Scottish Executive, Analytical Services Division Transport Statistics, compiles data on motorcycle casualties. During one year, monthly casualties resulting from motorcycle accidents in Scotland for built-up roads and non– built-up roads were  as follows.

a. Without doing any calculations, make an educated guess at which of the two data sets, built-up or non–built-up, has the greater variation.

b. Find the range and sample standard deviation of each of the two data sets. Compare your results here to the educated guess that you made in part (a).

Month January February March April May June July August September October November December Built-up Non-built-up 25 16 38 9 38 26 48 73 72 91 69 71 28 19 12 56 61 52 50 90 67 51 64 40