Question

seat-belt usage across different road types
road type\tyes\tno\ttotal
highway\t70\t30\t100
city\t50\t50\t100
rural\t60\t40\t100
total\t180\t120\t300
what is the joint frequency of drivers not using seat belts on rural roads?
40
40%
30
30%

Explanation:

Step1: Identify the relevant cell

We look at the table for the row corresponding to "Rural" road type and the column corresponding to "No" (not using seat belts).

Step2: Read the value

The value in that cell is 40.

Answer:

40