Question

At a high school, the average grade for the English 10 provincial is 64, with a standard deviation of 10. If 20 students scored between 73 and 86 on the exam, how many students took the exam? Use z scores in your solution

Answer 1

determine the normalCDF of (73,86,64,10)

Answer 2

or, if you dont have a ti83 or similar ...

zero out the mean and divide by the sd

Answer 3

\[z=\frac{x-\bar x}{\sigma}\]

Answer 4

I get 0.17

Answer 5

me too :)

so, 17% of the total number of students fall in that range

17% of N = 20, what is N?

Answer 6

.17 N = 20

N = 20/.17; and round up

Answer 7

118 students took the exam?

Answer 8

yep

Answer 9

Wow, thank you so much!!

Answer 10

good luck ;)