Question

Find the mean of 12, 17, 31, 25, 15. Find the resulting mean if observations is decreased by 2.

Answer 1

Given: Data: 12, 17, 31, 25, 15 (n = 5).

Sum = 12 + 17 + 31 + 25 + 15

= 100

Mean = `100/5`

= 20

If observation is decreased by 2:

New sum

= 100 – 5 × 2

= 90 

⇒ New mean

= `90/5`

= 18

Or

Use property:

20 – 2

= 18