# Stats help suppose you are working with a data set that is normally

Original question

Stats help Suppose you are working with a data set that is normally distributed, with a mean of 300 and a standard deviation of 44. Determine the value of x from the following information.

(a) 70% of the values are greater than x
(b) x is less than 13% of the values.
(c) 25% of the values are less than x
(d) x is greater than 52% of the values.

According to the Air Transport Association of America, the average operating cost of an MD-80 jet airliner is \$2,087 per hour. Suppose the operating costs of an MD-80 jet airliner are normally distributed with a standard deviation of \$175 per hour.

Round the value of z to 2 decimal places.

(a) At what operating cost would only 20% of the operating costs be less?

(b) At what operating cost would 65% of the operating costs be more?

(c) What operating cost would be more than 85% of operating costs?

in a recent year, the average price of a Microsoft Windows Upgrade was \$90.28 according to PC Data. Assume that prices of the Microsoft Windows Upgrade that year were normally distributed, with a standard deviation of \$8.53. If a retailer of computer software was randomly selected that year:

Round the values of z to 2 decimal places. Round your answers to 4 decimal places, the tolerance is +/-0.0001.

(a) What is the probability that the price of a Microsoft Windows Upgrade was below \$80?

(b) What is the probability that the price was above \$95?

(c) What is the probability that the price was between \$83 and \$87?

According to a report by Scarborough Research, the average monthly household cellular phone bill is \$60. Suppose local monthly household cell phone bills are normally distributed with a standard deviation of \$11.35.
(a) What is the probability that a randomly selected monthly cell phone bill is more than \$85?
(b) What is the probability that a randomly selected monthly cell phone bill is between \$45 and \$70?
(c) What is the probability that a randomly selected monthly cell phone bill is between \$65 and \$75?
(d) What is the probability that a randomly selected monthly cell phone bill is no more than \$40?

Round the values of z to 2 decimal places. Round your answers to 4 decimal places, the tolerance is +/-0.0001.

(a)
P(x > 85) =
(b)
P(45 < x < 70) =
(c)
P(65 < x < 75) =
(d)
P(x ≤ 40) =

Tompkins Associates reports that the mean clear height for a Class A warehouse in the United States is 22 feet. Suppose clear heights are normally distributed and that the standard deviation is 5 feet. A Class A warehouse in the United States is randomly selected.
(a) What is the probability that the clear height is greater than 17 feet?
(b) What is the probability that the clear height is less than 13 feet?
(c) What is the probability that the clear height is between 26 and 32 feet?

Round the values of z to 2 decimal places.Round your answers to 4 decimal places.

(a)
P(x > 17) =
(b)
P(x < 13) =
(c)
P(26 ≤ x ≤ 32) =

AND THEN IF YOU WOULDN’T MIND SHOWING WORK FOR A COUPLE OF THESE PROBLEM BELOW I JUST WAN TO GET A BETTER IDEA OF HOW TO  CALCULATE I DON’T KNOW IF I have to use the probability table or not.

Determine the probabilities for the following normal distribution problems.

Round the values of z to 2 decimal places.Round your answers to 4 decimal places.

(a) μ = 604, σ = 56.8, x ≤ 635:
(b) μ = 48, σ = 12, x < 20:
(c) μ = 111, σ = 33.8, 100 ≤ x < 150:
(d) μ = 264, σ = 10.9, 250 < x < 255:
(e) μ = 37, σ = 4.35, x > 35:
(f) μ = 156, σ = 11.4, x ≥ 170: