Question

If you know the answer put and explanation for it please thank you

Answer 1

14 students have to retake the test

Explanation:

to calculate the mean mark as

sum of ( product of mark and frequency ) ÷ total

mean =
`(14(2)+15(10)+16(2)+17(3)+18(13))/(30)`

=
`(28+150+32+51+234)/(30)`

=
`(495)/(30)`

= 16.5

students who score less than 16.5 will retake the test , that is

2 scored 16 , 10 scored 15 , 2 scored 14

number who have to retake test = 2 + 10 + 2 = 14