Question

Work out the overall mean for both classes.
Calculator is allowed.

Answer 1

68%

Explanation:

the mean is calculated as

mean =
`(sum)/(count)`

calculate the sum for both classes

class 1

`(sum)/(20)` = 64 ( multiply both sides by 20 )

sum = 1280

class 2

`(sum)/(10)` = 76 ( multiply both sides by 10 )

sum = 760

combine the 2 sums and divide by count of both classes for overall mean

overall mean =
`(1280+760)/(30)` =
`(2040)/(30)` = 68%