Question 9
Your answer is INCORRECT.
Suppose that prior to conducting a coin-flipping experiment, we suspect that the coin is fair. How many times would
we have to flip the coin in order to obtain a 90% confidence interval of
width
of at most .16 for the probability of
flipping a head?
a)
64
b)
106
c)
111
d)
65
e)
105
f)
None of the above

Question 10
Your answer is CORRECT.
It has been observed that some persons who suffer from common colds are diagnosed with it again within one year
of the first episode. This is due, in part, to damage from the first episode. In order to examine the percentage of the
persons who suffer from common colds a second time, a random sample of 1200 people who suffered from
common colds was collected. It was observed that 17 of them again suffered from common colds within one year.
Select a 90% confidence interval for the true proportion of those who suffer a second episode.

10/31/2018
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f)
None of the above
Question 11
Your answer is CORRECT.
When solving for the sample size required to estimate
p
to within a particular margin of error, under what
circumstances do we use p̂ = .5?
.

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