In: Statistics and Probability
A sample of size 25 will be drawn from a population with mean 34 and standard deviation 8. Find the probability that x− will be greater than 36.
Solution :
mean = 
 = 34
standard deviation = 
 = 8
n = 25

= 
 = 34  

= 
 / 
n = 8/ 
25 = 1.6
P(
>36) = 1 - P(
< 36 )
= 1 - P[(
- 
) / 
< (36 -34) / 1.6]
= 1 - P(z < 1.25 )
= 1 - 0.8944 = 0.1056
Probability =0.1056