statistics
posted by Zelinka on .
A random sample of n= 16 scores is selected from a normal distribution with a mean of u=50 and a standard deviation of q=10. A. what is th probability that the sample mean will have a value between 45 and 55? B. What is the probability that a sample mean will have a value between 488 and 52? C. What range of value has a 95% probability of containing the sample mean?

Z = (mean1  mean2)/standard error (SE) of difference between means
mean1 = sample mean
SEdiff = √(SEmean1^2 + SEmean2^2)
SEm = SD/√(n1) (You can use n)
If only one SD is provided, you can use just that to determine SEdiff.
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions related to the Z scores you found.