If the mean of five observations x , x +2, x +4, x +6, x +8, is 11, then the mean of first three observations is

Question

Philoid · Accepted Answer

First, you need to solve for x:

= 11

x + x + 2 + x + 4 + x + 6 + x + 8 = 55

5x + 20 = 55

5x = 35

x = 7

Now, substitute for x in each of the last three terms:

x + 4 + x + 6 + x + 8

(7 + 4) + (7 + 6) + (7 + 8)

(11) + (13) + (15)

= 13

The mean is 13