Hi, new here! Was wondering if I am right, I would
I would rather try things out as far as they can go, and then ask for help!
I am having problems on a statistics problem, that goes like this:
Suppose that a random variable X observes normal distribution N~(58.2, 12.55).
For this I find the z-score. Z=X-M/S, X=random variable, M=mean, S=standard deviation. So, Z=X-M/S = 25-58.2/12.55= -2.65. This is where I am confused. After this I have P(X>25)= 0.50-P(-2.65<X<0)= 0.004. I am not sure if I am right on this.
The second part of the question, still keeping the same mean and standard deviation, goes like this:
Calculate P(49.6<X<65.3) I converted each X into a z-score:
Z=65.3-58.2/ 12.55= 0.56
Z=49.6-58.2/ 12.55= -0.69
Then I looked up each z-score in a normal table in my statistics book to find the percentage that corresponds to each z-score: (Did I do my notation right, by the way?)
For z-score 0.56: P(0<X<0.56)= 0.2123
For z-score -0.69: P(0<X-0.29)= 0.1141
Finding z-scores then looking in a normal table to find percentages/probability is easy, but I get lost here. I don't know how to "complete" the problem and answer what is being asked of me. Help please? What am I lost on?