P(z < c) = 0.6915 Find c

Question

For a standard normal distribution, given:

P(z < c) = 0.6915

Find c.

Answer 1

Hi Monica,

Your answer can be achieved in one of two ways: by hand or by technology.

By hand, you will have to look in the Z-table for the area that corresponds to 0.6915. I found that the z-score is 0.50 by using the table. Then you take the formula for z-score and work backward to get the c value. Unless they did not give you a mean or standard deviation. In that case, the answer is c=0.50.

By calculator, you can use the invnorm function. Invnorm(.6915,0,1) = 0.50.

I hope that helps.