Based on the pie chart shown on the right, Mrs Goh told Mr Goh that male drivers are worse drivers than female drivers. Explain why Mrs Goh should not make such a statement. What could be a better mathematical measure to make a conclusion whether the male or female drivers are worse drivers?

1. Identify why the conclusion from the pie chart is not valid

The pie chart compares only the numbers of male and female drivers involved in accidents. It does not take into account the total number of male and female drivers. If there are more male drivers overall, a larger male sector does not necessarily mean male drivers are worse drivers.

2. State a better mathematical measure for comparison

Use accident rates or percentages within each gender:
$\text{accident rate for males}=\frac{\text{number of male drivers involved in accidents}}{\text{total number of male drivers}},$
$\text{accident rate for females}=\frac{\text{number of female drivers involved in accidents}}{\text{total number of female drivers}}.$