Question

The mean length of 6 childrens' big finger is 12.6cm.

The mean length of 8 adults' big finger is 16.7cm.
What is the mean length (rounded to 2 DP) of these 14 people's big finger?

Answer 1

14.94 cm ( to 2 dec. places )

We require the sum totals of the 2 groups before calculating the mean of all 14

using mean =
`(sum)/(count)`

Children's sum

12.6 =
`(sum)/(6)`( cross-multiply )

sum = 6 × 12.6 = 75.6

Adult's sum

16.7 =
`(sum)/(8)`( cross- multiply )

sum = 8 × 16.7 = 133.6

Total sum of all 14 = 75.6 + 133.6 = 209.2

mean =
`(209.2)/(14)` = 14.94 cm