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AP Statistics
Continuous Distributions Review
1) In a recent study, it was found that in one town the number of hours that a typical 10-year-old child watches
television per week is normally distributed with a mean of 12 hours and a standard deviation of 1.5
hours. If Gary is a typical 10-year-old child in this town, what is the probability that he watches
between 9 and 14 hours of television per week?
.8860
2) An electric circuit is designed so that voltage levels are uniformly distributed between 5.00V and 9.00V.
Find the probability that a randomly selected voltage level is between 7.00V and 8.50V.
.375
3) If heights of adult males are normally distributed with a mean of 70.2 inches and a standard deviation of 4.2
inches, and 95% of all adult males satisfy a minimum height requirement for police officers, what is
that minimum height requirement?
63.29 inches
4) Suppose that a distribution is shown to the right.
a) P x  1  .25
b) P x  2  .375
c) P 1  x  3  .75
.5
.25
1
2
3
5) In studying ocean conditions, the Bureau of Fisheries found that for one location, the August water
temperatures (in degrees Fahrenheit) were normally distributed with a mean of 83.6 and a standard
deviation of 2.4. Find the temperature that is exceeded 10% of the time.
86.68˚F
6) A service station is located at one end of a 4-kilometer tunnel. Any vehicle breakdown requires servicing is
equally likely to occur at any point in the tunnel.
a) What is the probability that a service call will involve a vehicle located in the first 1.8 km?
.45
b) What is the probability that a service call will involve a vehicle located at least halfway in
the tunnel?
.5
7) The amount of money spent weekly on cleaning, maintenance and repairs at a large restaurant was observed
over a long period of time to be approximately normally distributed with mean of $615 and
standard deviation of $42. The amount of money spent weekly on salaries is also approximately
normally distributed with a mean of $5000 with standard deviation of $205. If the restaurant
budgets $6000 for cleaning, maintenance, repairs and salaries, what is the probability that the
actual costs will exceed the budgeted amount?
.0329