For the following frequency distribution what is X X f 3034

For the following frequency distribution, what is X?

  X f

30-34 1

25-29 1

20-24 3

15-19 2

10-14 1

Solution

Note that

Sum(x) = Sum (Mi fi)

where

Mi = the midpoints
fi = the frequencies

We follow these steps:

1. Get the midpoint of each class.

These are 32, 27, 22, 17, 12.

2. Multiply each midpoint to the frequency.

These are now: 32*1, 27*1, 22*3, 17*2, 12*1.

3. Sum the results of step 2.

Sum(x) = 171 [answer]