'x' normally distributed, mean 38, standard dev. 9: find....

SONCEE said:

Let x = age of employee . Assume x is normally distributed with a men of 38 and a standard of 9

1) what fraction of employees are under the age of 40

2) if one employee is picked at random, what is the probability that he will be under the age of 40.

3) If a simple random sample of 100 employee is picked, what is the probability that the sample mean will be less than 40

All i got is this

2) z= 40-38/9 = 0.222 = 0.871 ---- Where/how did you get this


3) z= 39-38/9 = 0.111= 0.54 ---- Where/how did you get this

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