Question

The mean length of 10 childrens' big finger is 8.1cm.

The mean length of 11 adults' big finger is 14.1cm.
What is the mean length (rounded to 2 DP) of these 21 people's big finger?​

Answer 1

• The mean length of 10 children's big finger is 8.1 cm

Average length of all the 10 children's finger is (8.1×10) cm = 81 cm.

• The mean length of 11 adult's big finger is 14.1 cm

Average length of all the 11 adult's big finger is (14.1×11) cm =155.1

• Mean length of these 21 people's big finger is
• 
  `((81 + 155.1))/(21) = 11.242857`
• Hence, 11.24 is the right answer.