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Quiz #2 STA2023
Basic Normal Curves
Provide all of your answers/explanations/work in the spaces provided. However,
you may attach additional work if you want to. Write your quiz up with your name, date,
and the time and days that you attend the class. Show all work for full credit. Your
submitted quiz should be neat, clear and detailed. It should not be a rough draft. When
in doubt, include as much relevant, correct information pertaining to your answer as
possible. Remember, start early and seek out help if you “get stuck.” There are two
printed pages to this quiz.
1. (2 pts.) Using the Empirical Rule only, state the area under the Standard Normal
Curve between
1
−
and 1.
2. (3 pts.) Calculate P(z >
65.0
−
). Round your answers to four decimal places. Don’t
put down just the answer, i.e., show all work for full credit!
3. The mean number of hours American workers spend on the computer is 3.1 hours per
workday. Assume that the standard deviation is 0.5 hour and that the variable is
normally distributed.
a) (4 pts.) Clearly, with detail, and using appropriate labeling notation, sketch by
hand the distribution of hours that American workers spend on the computer per
weekday.
