
Probability with Z Score
Hey there, I have two fairly simple questions for you, one I have an answer that id like checked, the other I need more help with :)
Women's Weight are normally distributed with a mean of 143 & a standard deviation of 29lb.
a)If one woman is randomly Selected, find the probability that her weight will be GREATER than 150 lbs
The way I did this is as follows:
P(X>150)
P((x143)/29)>(150143)/29))
I solved the one on the right and got .24137931, which is in relation to a z score. I have a chart for this, and I look up .24 and get a probability of .5948. I want everything on the other side right, so I subtract that from 1 and get .4052(or 41%) as my answer
Did I do it correctly? I have no way to check my work.
Women's Weight are normally distributed with a mean of 143 & a standard deviation of 29lb.
b) Find the probability that 12 randomly selected women will have a mean that will be GREATER than 150 lbs
This one is very confusing to me, and im not entirely sure where to start.
EDIT:
So after some thinking and searching i tried the following (still need someone to check it, as I have no way to myself)
to get the new standard deviation i did 29/12^(1/2) (square root of 12)
8.3715789, which I rounded up to 8.4
(150143)/8.4 = 0.833333333
I look at my chart for .83 and get .7939
Then 1.7939 to get .2061, or 21%
I appreciate all help that comes my way :)

Don't be afraid; you got both right(Nod)