A test given to 200 students has a mean of 300 and a standard deviation of 50.

A. You have a score of x=400, find Z.

B. How many scored more than you?

Question

A test given to 200 students has a mean of 300 and a standard deviation of 50.

A. You have a score of x=400, find Z.

B. How many scored more than you?

anonymous · Answer

B is a seperate question...I got the answer for A as 2 and I'm confused what B is

amistre64 · Answer

we have all the info for a; except for the formula to find z

anonymous · Answer

Z=(x-mean)/SD

is that what you are asking for?

amistre64 · Answer

thats the one.  that 200 is clutter and can be ignored

x = 400, mean = 300; sd = 50

amistre64 · Answer

part b requires you to become familiar with using a ztable, or your calculator :)

anonymous · Answer

I don't get how to find part b

amistre64 · Answer

the ti83 stuff would have something to do with

2nd, VARS, normalCDF and entering in

normalCDF(low,high,mean,sd)

the low point is 400, the high point is an arbitrary huge number (9999 tends to work fine) and the mean and sd you already have

amistre64 · Answer

otherwise we use the zscore and a ztable

amistre64 · Answer

the tables differ from book to book depending depending on the authors taste.  So unless we know what table format you have a walk thru is going to be rather absract

amistre64 · Answer

lol, not only do i mistype words, apparently i forget what words I have typed and start repeating them :)