posted by luke on .
All deal with a random variable X that follows a normal probability distribution with mean equal to 37 and a standard deviation of 5.
Compute P(X < 39)
Compute P(X < 29 or X > 41)
Compute P(X > 30)
Find the 42nd percentile for this distribution.
Z = (score-mean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions/probabilities related to the Z scores.
Either-or probabilities are found by adding the individual probabilities.
For last Q, Start with table (.42) and insert Z score into above equation.
PsyDAG, right on thanks