In: Statistics and Probability
Assume that blood pressure readings are normally distributed with a mean of 124 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 126. Round to four decimal places.
Solution :
Given that ,
mean =
= 124
standard deviation =
= 9.6
=
/
n = 9.6 /
144 = 0.8
P(
< 126) = P((
-
) /
< (126 - 124) / 0.8)
P(z < 2.5)
= 0.9938
Probability = 0.9938