find Z score

#1
I am lost...

Here's the question and I am not sure where to start:-

The scores on a university exam are normally distributed with a mean of 62 and a standard deviation of 11. The bottom 5% of students will fail the course. What is the lowest mark that a student can get in order to pass.

How to I find z in the first place.....and then I assume that they are asking for X!

z=(x-mu)s

I am assuming that my mu is 62
S= 11

help!
 

vinux

Dark Knight
#2
It is quite an easy one.

Use the spreadsheet function =NORMSINV(.95) ( Open Office, i think this will work in excel too)
you will get the value as

P[Z<1.64] = .95 and Z = (X-mu)/S
=> 1.64 = (X - 62)/11

:rolleyes: