Question 130789
A coin was flipped 60 times and came up heads 38 times. 
(a) At the .10 level of significance, is the coin biased toward heads? Show your decision rule and calculations. 

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p-hat = x/n = 38/60 = 19/30
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Ho: p = 1/2
Ha: p > 1/2
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Critical value: z = 1.28
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Test statistic: z(19/30) = (0.633333-0.5)/sqrt[(.5)(.5)/60] 
= 0.13333*sqrt(60)/0.5 = 2.065
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Since test statistic is greater than critical value, Reject Ho.
The coin is biased toward heads.
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(b) Calculate a p~value and interpret it.
P(2.065 < z < 10) = 0.019...
The probability the test results could have produced even stronger
evidence of the coin's bias towards heads is 0.019...
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Cheers,
stan H.