22. Cerebral Blood Flow Cerebral blood flow (CBF)

in the brains of healthy people is normally distributed with a mean of 74 and a standard deviation of 16. A random sample of 25 stroke patients resulted in an average CBF of 69.7. If we assume that there is no difference between the CBF of healthy people and those who have had a stroke, what is the probability of observing an average of 69.7 or an even smaller CBF in the sample of 25 stroke patients?