Question

1)Given that x is a normal variable with mean μ = 46 and standard deviation σ = 6.2, find the following probabilities. (Round your answers to four decimal places.)

(a)  P(x ≤ 60)


(b)  P(x ≥ 50)


(c)  P(50 ≤ x ≤ 60)

2)The Customer Service Center in a large New York department store has determined that the amount of time spent with a customer about a complaint is normally distributed, with a mean of 9.9 minutes and a standard deviation of 2.4 minutes. What is the probability that for a randomly chosen customer with a complaint, the amount of time spent resolving the complaint will be as follows. (Round your answers to four decimal places.)

(a) less than 10 minutes


(b) longer than 5 minutes


(c) between 8 and 15 minutes

3)According to Harper's Index, 55% of all federal inmates are serving time for drug dealing. A random sample of 16 federal inmates is selected.

(a) What is the probability that 10 or more are serving time for drug dealing? (Round your answer to three decimal places.)


(b) What is the probability that 5 or fewer are serving time for drug dealing? (Round your answer to three decimal places.)


(c) What is the expected number of inmates serving time for drug dealing? (Round your answer to one decimal place.)

Answer 1