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 = [tex]\frac{sum}{count}[/tex]
Children's sum
12.6 = [tex]\frac{sum}{6}[/tex]( cross-multiply )
sum = 6 × 12.6 = 75.6
Adult's sum
16.7 = [tex]\frac{sum}{8}[/tex]( cross- multiply )
sum = 8 × 16.7 = 133.6
Total sum of all 14 = 75.6 + 133.6 = 209.2
mean = [tex]\frac{209.2}{14}[/tex] = 14.94 cm
