Question

1) Automobile Workers A worker in the automobile industry works an average of 42.9 hours per week.  If the distribution is approximately normal with a standard deviation of 1.4 hours, what is the probability that a randomly selected automobile worker works less than 41 hours per week? Round the answer to at least four decimal places.

P(X<41)

Teachers' Salaries The average annual salary for all U.S. teachers is 47750. Assume that the distribution is normal and the standard deviation is 5680. Find the probabilities round the answer to at least four decimal places.

(a)A randomly selected teacher earns between 34000 and 43000 a year. P(34000 _<X_<43000)=

I can't find the answer because I don't think I have the right calculator. Please help.

Answer 1

1) Let ,

Now ,

; From standard normal distribution table

Therefore , the probability that a randomly selected automobile worker works less than 41 hours per week is 0.0869

2)

Let ,

Now ,

; From standard normal distribution table