Let X be a normal random variable with mean 80 and standard deviation 5. What is the probability X is greater than 87? Less than 74?
I understand how to compute the z score but I'm confused as to when I have to keep the number from the z-table or subtract 1
z= x-μ /σ
The Attempt at a Solution
z = 1.4
P (z > 87 ) = ??
I found the z score to be 0.9192 but do I keep this value as my answer or do I do 1 - 0.9192
P (z < 74)= ??
again, I found z score to be .1151
So I keep this value or 1 - 0.1151 and why?