A new muscle relaxant is available. Researchers from the firm developing the relaxant have done studies that indicate that the time lapse between administration of the drug and beginning effects of the drug is normally distributed, with mean of 38 minutes and standard deviation of 5 minutes.
A. The drug is administered to one patient selected at random. What is the probability that the time it takes to go into effect is less than 35 minutes?
B. The drug is administered to a random sample of 10 patients. What is the probability that the average time before it is effective for all 10 patients is less than 35 minutes?

Francesca39,

Welcome to this beautiful site, first!
Did you try to do the sum? What did you find? Where do you face the problem, in the sum?

Can you solve first degree probability sums?