1
STA2023 – Chapter 6 Practice Activity
1.
Suppose the most recent census reported that ages of all Alachua County residents are normally
distributed with an average of 28.1 years and a standard deviation of 2.5 years.
To verify the accuracy of
the census results, a statistics student collected age data from a random sample of 500 Alachua County
residents and found the average age of these 500 people to be 27.8 years, with a standard deviation of 2.3
years.
Provide an appropriate symbol for each of the numerical values given in this scenario.
28.1 years:
2.5 years:
500 people:
27.8 years:
2.3 years:
2.
The amount of Jen’s monthly phone bill is normally distributed with a mean of $61 and a standard
deviation of $12.
Use the 689599.7 rule to answer each of the following questions.
You should draw a
welllabeled Normal curve for each part.
A.
Approximately what percent of the time is Jen’s phone bill between $49 and $61?
B.
Approximately what percent of the time is Jen’s phone bill less than $37?
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 Spring '08
 Ripol
 Statistics, Normal Distribution, Standard Deviation, Jen, Rhesus monkeys, welllabeled Normal curve, adult rhesus monkeys

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