# Thread: Standard Normal Distribution

1. ## Standard Normal Distribution

I'm confused on determining an z score,

For the graph of a standard normal distribution the cumulative area to the left of a z score is 0.4, what is the cumulative area of the right of that Z score?

z = 0.4, would the right area of the score be an -0.4? How should I start, by placing and 0 between 0.4 or puting an -0.4 in right? What should I do next?

2. Originally Posted by Lydia08
I'm confused on determining an z score,

For the graph of a standard normal distribution the cumulative area to the left of a z score is 0.4, what is the cumulative area of the right of that Z score?

z = 0.4, would the right area of the score be an -0.4? How should I start, by placing and 0 between 0.4 or puting an -0.4 in right? What should I do next?<--No.
Hi Lydia,

Read the question again carefully. It is helpful to sketch a normal graph in problem like this.

One fact you should know is that the cumulative area under the entire normal curve is 1. So if the area to the left of a certain z score is 0.4, what is the area to the right of it? (Remember they should add up to 1).

Note: The cumulative area is 0.4 does not mean the z score is 0.4.