Question

determine the value of C

P(-c<z<c)= 0.9736 the two marks that are < have a line under them.

Can someone show me how to do this problem.
Thank you

Answer 1

Since the bell curve is symmetric, you have
p(0<Z<c) = .4868
Look up .4868 and you see that c=2.221

Or, you can see that 1-.9736 = .0264.
Half of that is 0.0132
Add that to the .9736 and you have .9868
Look that up, and you have Z=2.22

You can play around with Z table stuff at

http://davidmlane.com/hyperstat/z_table.html

It makes visualizing this stuff very easy.