Question

Find the mean of all odd numbers from 5 to 20. Find the new mean when each number is multiplied by 4. 

Answer 1

The numbers are: 
5, 7, 9, 11, 13, 15, 17, 19 

`barx = (x_1 + x_2 + x_3 + .... + x_n)/n`

n = 8

⇒ `barx = (5 + 7 + 9 + 11 + 13 + 15 + 17 + 19)/8 `

⇒ `barx = 96/8`

⇒ `barx = 12`

Therefore, Mean of odd numbers from 5 to 20 = 12 

If numbers are multiplied by 4, the numbers are: 
20,28, 36, 44, 52, 60, 68, 76 

`barx = (x_1 + x_2 + x_3 + .... + x_n)/n`

n = 8

⇒ `barx = (20 + 28 + 36 + 44 + 52 + 60 + 68 + 76 )/8`

⇒ `barx = 384/8`

⇒ `barx = 48`

Therefore, Mean of odd numbers from 5 to 20 when multiplied by 4= 48