Question

The mean length of 4 childrens' big finger is 14cm. The mean length of 9 adults' big finger is 16.1cm. What is the mean length (rounded to 2 DP) of these 13 people's big finger?

Answer 1

The mean length of the 13 people's big finger is 15.45 cm

Explanation:

Given;

mean length of 4 childrens' big finger, x' = 14cm

mean length of 9 adults' big finger is 16.1cm, x'' = 16.1cm

Let the total length of the 4 childrens' big finger = t

`x' = (t)/(n) \\\\x' = (t)/(4)\\\\t = 4x'\\\\t = 4 *14\\\\t = 56 \ cm`

Let the total length of the 9 adults' big finger = T

`x'' = (T)/(N) \\\\x'' = (T)/(9)\\\\T = 9x''\\\\T = 9*16.1\\\\T = 144.9 \ cm`

The total length of the 13 people's big finger = t + T

= 56 + 144.9

=200.9 cm

The mean length of these 13 people's big finger;

x''' = (200.9) / 13

x''' = 15.4539 cm

x''' = 15.45 cm (2 DP)

Therefore, the mean length of the 13 people's big finger is 15.45 cm