The price of a gallon of milk follows a normal distribution with a mean of 3.20 and a standard
deviation of 0.10. Find the price for which 12.3 of milk vendors exceeded.
A) 3.316 B) 3.084 C) 3.238 D) 3.215
Q. 2The tread life of a particular brand of tire is a random variable best described by a normal
distribution with a mean of 60,000 miles and a standard deviation of 3000 miles.
What warranty
should the company use if they want 96 of the tires to outlast the warranty?
A) 63,000 miles B) 65,250 miles C) 54,750 miles D) 57,000 miles
Q. 3The tread life of a particular brand of tire is a random variable best described by a normal
distribution with a mean of 60,000 miles and a standard deviation of 2500 miles.
What is the
probability a certain tire of this brand will last between 54,750 miles and 55,500 miles?
A) .4649 B) .9813 C) .4920 D) .0180
Q. 4The tread life of a particular brand of tire is a random variable best described by a normal
distribution with a mean of 60,000 miles and a standard deviation of 1300 miles.
What is the
probability a particular tire of this brand will last longer than 58,700 miles?
A) .1587 B) .7266 C) .2266 D) .8413
Q. 5The preventable monthly loss at a company has a normal distribution with a mean of 7800 and
a standard deviation of 30. A new policy was put into place, and the preventable loss the next
month was 7620.
What inference can you make about the new policy?
A) Because the probability that the monthly loss would be as low as 7620 is not very small,
the new policy is not working.
B) While the probability that the monthly loss would be as low as 7620 is small, it is not
unexpected.
C) Because the probability that the monthly loss would be as low as 7620 is small, the new
policy is working.
D) The new policy is probably less effective than the one it replaced.
Q. 6Before a new phone system was installed, the amount a company spent on personal calls
followed a normal distribution with an average of 500 per month and a standard deviation of
50 per month.
Refer to such expenses as PCE's (personal call expenses). Find the probability
that a randomly selected month had PCE's below 350.
A) 0.3000 B) 0.9987 C) 0.0013 D) 0.7000
Q. 7Before a new phone system was installed, the amount a company spent on personal calls
followed a normal distribution with an average of 700 per month and a standard deviation of
50 per month.
Refer to such expenses as PCE's (personal call expenses). Find the point in the
distribution below which 2.5 of the PCE's fell.
A) 17.50 B) 682.50 C) 602.00 D) 798.00
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