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Math 147  Fall 1997  Test 3
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Show ALL your work. Solutions with no work where it is necessary will receive
NO
credit. If you need extra paper
raise your hand and ask one of the proctors for some. A normal table is provided at the end of the test. Good Luck.
For questions 110 circle the answer which best completes the sentence or answers the question. (3 pts each)
1.
A fair coin is tossed one hundred times and the number of heads is recorded. The same coin is then
tossed 1000 times and the number of heads is recorded. We expect,
(a) the difference between 50 and the number of heads in the first trial to be larger than the
difference between 500 and the number of heads in the second trial.
(b) to get exactly 500 heads in the second trial.
c.
the chance error expressed as a percentage of the number of tosses to be smaller in the first trial than in the
second trial.
d.
all of the above statements.
a.
none of the above statements.
2.
A box contains 99 zeros and 1 one. If we make draws from this box with replacement,
a.
the probability histogram for the sum of the draws ( when put in standard units) will follow the normal
curve after a small number of draws.
b.
then the probability histogram for the numbers in the box is close to the normal curve if the number of
draws is very large.
c.
we can use the binomial formula to compute the chance of getting exactly 3 ones in 10 draws.
d.
both (a) and (c) are true.
e.
both (a) and (b) are true.
3.
When thinking about sample surveys we should remember,
a.
a parameter is a numerical fact about a sample, subject to chance variation.
b.
the researcher uses the population to compute a statistic.
c.
that the parameter may be subject to sampling bias.
d.
simple random sampling means drawing the subjects at random without replacement.
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both (c) and (d).
4.
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 Fall '07
 Klimko
 Math, Normal Distribution, Standard Error, A. B., psychology class

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