Understanding Basic Statistics 6th Edition by Charles Henry Brase,Corrinne Pellillo Brase

Exercise 85

Drugs: Effects 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 . = 38 minutes and standard deviation = 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 35 minutes or less
(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 35 minutes or less
(c) Comment on the differences of the result in parts (a) and (b).