Normal Distribution

[mayday]

Assume x has a normal distribution, and find the indicated probability. The mean is 200, standard deviation 50. Find the following probability:

P(175<x<220)

This is how I worked it:

175-200/50= -.5

220-200/50= .4

convert to z scores: .3085 < x < .6554.....

Now I am lost. Please help!

[JohnM]

The -0.5 and 0.4 are z scores. Now use the normal distribution table to find the probability of getting z scores in between z= -0.5 and z = 0.4.

[mayday]

The -0.5 and 0.4 are z scores. Now use the normal distribution table to find the probability of getting z scores in between z= -0.5 and z = 0.4.

I'm lost. The normal distribution table?

[JohnM]

a.k.a. the Z table, most likely in the back of your textbook