Posted by Sarah on .
The weights of the fish in a certain lake are normally distributed with a mean of 11 lb and a
standard deviation of 6. If 4 fish are randomly selected, what is the probability that the mean
weight will be between 8.6 and 14.6 lb?
A) 0.0968 B) 0.4032 C) 0.3270 D) 0.6730

Statistics 
PsyDAG,
Z = (mean1  mean2)/standard error (SE) of difference between means
SEdiff = √(SEmean1^2 + SEmean2^2)
SEm = SD/√(n1)
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. 
Statistics 
Sarah,
i still don't get how to do it?