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 99% confidence interval of width of at most .18 for the probability of flipping a head? (note that the z-score was rounded to three decimal places in the calculation) a) 164 b) 205 c) 167 d) 212 e) 202 f) none of the above



Answer :

The coin is flipped at least 52 times in order to obtain a 99% confidence interval of width of at most . 18 for the probability of flipping a head.

Hence, Option F is correct answer.

In a sample with a number n of people surveyed with a probability of a success of π , and a confidence level of (1-α), we have the following confidence interval of proportions.

[tex]\pi[/tex] ± z[tex]\sqrt{\frac{\pi \p(1-\pi )}{n} }[/tex]

z is the z-score that has a pvalue of [tex]1-\frac{\alpha }{2}[/tex]

Since, the coin is fair, so [tex]\pi =0.5[/tex].

The margin of error is:

[tex]M=z\sqrt{(\frac{\pi (1-\pi )}{n} )}[/tex]

99% confidence level:

So [tex]\alpha =0.01[/tex] ,z is the value of Z that has a p value of 1-[tex]\frac{0.01}{2}[/tex]=0.995,

so Z= 2.575

How many times would we have to flip the coin ?

We have to flip the coin in order to obtain a 99% confidence interval of width of at most 18 for the probability of flipping a head at least n times.

n is found when M=0.18 .

So

M=[tex]z\sqrt{\frac{\pi (1-\pi )}{n} }[/tex]

[tex]0.18=2.575\sqrt{\frac{0.5*0.5}{n} }[/tex]

[tex]0.18\sqrt{n} =2.575*0.5[/tex]

[tex]\sqrt{n}=\frac{2.575*0.5}{0.18}[/tex]

[tex]\sqrt{n} ^{2} =(\frac{2.575*0.5}{0.18} )^{2}[/tex]

n = 51.16

Thus, we have to flip the coin at least 52 times.

Learn more about the Probability here: https://brainly.com/question/24756209

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