Question

The rainfall (in mm) in a city on 7 days of a certain week was recorded as follows:

Day	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
Rainfall (in mm)	0.0	12.2	2.1	0.0	20.5	5.5	1.0

1. Find the range of the rainfall in the above data.
2. Find the mean rainfall for the week.
3. On how many days was the rainfall less than the mean rainfall.

Answer 1

i. Range = (20.5 − 0.0) mm

= 20.5 mm

ii. Mean rainfall = `(0.0 + 12.2 + 2.1 + 0.0 + 20.5 + 5.5 + 1.0)/7`

= `41.3/7`

= 5.9 mm

iii. For 5 days (i.e., Monday, Wednesday, Thursday, Saturday, Sunday), the rainfall was less than the average rainfall.