Out of 44
The 'Expectation' (mean value) is
To find the mean of a set of date we use the following method:
Remember, we can add numbers, we can add totals,
WE CANNOT ADD MEANS!
For the 44 boys in the class , we can find the sum of all their ages.
9 boys are all 10 years old, the sum of their ages is
15 boys are all 9 years old, the sum of their ages is
20 boys are all 8 years old:, the sum of their ages is
For the 44 boys, the sum of their ages is 385 years.