Posted by Sally on Thursday, November 10, 2011 at 2:33am.
Random variable X is normally distributed with mean 10 and standard deviation 2.
Compute the following probabilities.
a. Pr(X<10)
b. Pr(X<11.04)
I don't know where to start.

Math  Reiny, Thursday, November 10, 2011 at 8:26am
a) P(X<10) gives a zscore of (1010)/2 = 0
b) P(X<11.04) gives a zscore of (11.0410)/2 = .52
You must be given a table of "normal distribution" or have access to a program that duplicates the table or chart.
I use this one
http://davidmlane.com/hyperstat/z_table.html
You can use it directly without finding the zscores
e.g. for b)
1.
enter: mean: 10 , Sd: 2, click on below and enter 11.04 to get .698468
2.
enter: mean: 0 , Sd: 1 , click on "below" and enter the zscore of .52 to get .698468