Question

For the classes 18-19, 19-20, 20-21, 21-22, 22-23, and 23-24 with frequencies 4, 13, 15, 19, 17, and 6, the coordinate pair for the class 20-21 is:

Options

• (20.5, 15)

• (20.0, 15)

• (21.5, 15)

• (20.5, 19)

Answer 1

The class mark of 20-21 is \[ \frac{20+21}{2}=20.5 \] and its frequency is 15, so the point is (20.5, 15).