If systolic blood pressure (SBP) in the population is normally distributed with mean = 120 mm Hg and standard deviation = 15 mm Hg. a) If a sample of 38 people is selected, find the probability that...

If systolic blood pressure (SBP) in the population is normally distributed with mean = 120 mm Hg and standard deviation = 15 mm Hg.

a) If a sample of 38 people is selected, find the probability that the sample mean of SBP is higher than 139.5 mm Hg?

b) Find the 60th percentile value of SBP?