Question

The mean length of 7 childrens' index finger is 9.4cm.

The mean length of 4 adults' index finger is 14.8cm.
What is the mean length (rounded to 2 DP) of these 11 people's index finger?

Answer 1

Answer: 11.36 cm

Work Shown:

n = number of children = 7

a = average finger length of the children = 9.4 cm

m = number of adults = 4

b = average finger length of the adults = 14.8 cm

c = weighted average finger length of all 11 people

c = (n*a + m*b)/(n + m)

c = (7*9.4 + 4*14.8)/(7+4)

c = 11.3636363636363 approximately. The "36" goes on forever

c = 11.36 cm