Question 1186330
random variable is the blood pressure.
n=15 from a normal distribution is normally distributed itself with sample mean (for n=15) 128, same as pop. mean and sd of 23/sqrt(15) mm
-
z=(xbar-mean)/sigma/sqrt(n)
=(135-128)*sqrt(135)/23
=1.18
probability of that z or greater is 0.1190
It would not be common but not unusual to find that value.
If I found a value >135, what I would think of it would depend upon what my cutoff value for abnormal were, before I did the study. Since most cutoff values are <0.10, I would likely not consider the value abnormal.