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ctent we carl make äbout the p-value? Interpret this result. (4) (12.5 points):

ID: 3350854 • Letter: C

Question

ctent we carl make äbout the p-value? Interpret this result. (4) (12.5 points): Of the total population of those U.S. taxpayers who are audited, a population proportion of 80% end up paying more money in taxes. Assume that auditors are randomly assigned to cases, and that one of the ways to oversee the auditors is to monitor the percentage of cases that result in the taxpayer paying more taxes. (A) If a sample of 400 cases handled by an individual auditor has a sample perecentage of 77.0% of those she audited paying more taxes, at a 0.10 level of significance is there reason to believe her overall "pay more percentage might be some value other than 80%? For this find and show: hypothesis, test-value, critical-value, comparison logic, comparison selection and conclusion. (B) At the 90 % confidence level, construct and interpret the confidence interval.

Explanation / Answer

a)

Test and CI for One Proportion

Test of p = 0.8 vs p 0.8


Sample    X    N    Sample p           90% CI             Z-Value P-Value
1          308 400 0.770000    (0.735390, 0.804610)    -1.50   0.134

Using the normal approximation

TS = -1.50

critical value = 1.645

p-value = 0.134 > 0.10

we fail to reject the null hypothesis

b)

90% confidence interval - (0.735390, 0.804610)