Posted by **abc** on Sunday, March 16, 2014 at 8:27am.

Let X and Y be normal random variables with means 0 and 2, respectively, and variances 1 and 9, respectively. Find the following, using the standard normal table. Express your answers to an accuracy of 4 decimal places.

P(X>0.75)=

P(X≤−1.25)=

Let Z=(Y−3)/4. Find the mean and the variance of Z.

E[Z]=

var(Z)=

P(−1≤Y≤2)=

- Math (Partial) -
**PsyDAG**, Sunday, March 16, 2014 at 8:27pm
First two questions and last.

Z = (score-mean)/SD

SD^2 = variance

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability of the Z score.

- Math -
**abc**, Monday, March 17, 2014 at 4:47pm
P(X>0.75)= 0.2266

P(X≤−1.25)= 0.1056

Can't figure out these:

E[Z]=

var(Z)=

P(−1≤Y≤2)=

anyone?

- Math -
**Bane Havoc**, Tuesday, March 18, 2014 at 4:13pm
P(X>0.75)= 0.2266

P(X≤−1.25)= 0.1056

E[Z]= -1/4

var(Z)= 9/16

P(−1≤Y≤2)= ?

- Math -
**RVE**, Saturday, February 28, 2015 at 1:29pm
P(−1≤Y≤2)= 0.3413

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