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