Assume that blood pressure readings are normally distributed with a mean of 123 and a standard deviation of 9.6. If 144 people are randomly selected, find the probability that their mean blood pressure will be less than 125.

Answer 1

z = (125-123)/(9.6/sqrt(144)
z = 2/(9.6/12)
z = 2.5
z-table
1-.0062 =0.9938

Answer 2

Bardzo przydatny wpis, bede tego uzywał w swojej pracy!