has a normal distribution. Then the distribution of
X
is:
h)
Exactly normal for any n, Central Limit Theorem not needed
a)
Approximately normal for any n by the Central Limit Theorem
i)
Approximately normal for large enough n by the Central Limit Theorem
b) None of the above
1
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A sample of 500 batteries is tested and the average lifetime of this sample is found to
be 225 hours. Based on this information, you report that the average lifetime of all
batteries of this type is 225 hours, plus or minus 50 hours. The 225 hours in this
problem represents a:
a)
Parameter
a)
Statistic
7.
If the confidence level of a confidence interval decreases, then the margin of error:
b) Increases
c)
Decreases
d)
Does not change
8.
Suppose you have a confidence interval for the population mean. If the sample mean
X
were to increase (and everything else stayed the same) then the margin of error for
your confidence interval would:
a)
increase
b) decrease
e)
not change
9.
The amount of bias in a survey is included in the margin of error of the survey.
a)
True
b)
False
10. A survey is conducted to study the backgrounds of professional golfers. In particular,
the question is what percentage of professional golfers had parents who also played
golf. A random sample of 300 professional golfers were surveyed. It was found that
225 of them (75%) indicated that their parents played golf. Which of the following is
the population of interest?
f)
All professional golfers.
a)
All of the parents of professional golfers.
b) The 300 professional golfers surveyed.
c)
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 Spring '07
 rumseyjohnson
 Statistics, Normal Distribution, Standard Deviation

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