A random sample consists of eight tax filers who completed their tax forms on th
ID: 3179970 • Letter: A
Question
A random sample consists of eight tax filers who completed their tax forms on their own. Their forms were found to have 1, 3, 2, 4, 0, 2, 1, and 2 mistakes, respectively. Determine the 90% confidence interval for the mean number of mistakes that a tax filer will make in his/her forms if they're completed on his/her own. Assume the distribution of the number of mistakes in tax forms is approximately normal. A random sample of size 90 yields a sample proportion 0.3. (a) Is the sample size large enough to construct a large-sample confidence interval for p? (b) Construct a 99% confidence interval for p.Explanation / Answer
here for 7 degree of freedom and 90% CI, t=1.8946
hence confidence interval =mean +/- t*std error =1.040 ; 2.710
b)here np=90*0.3=27>10 and npq=>10 hence it fullfill the requirement
here p =0.3
and std error =(p(1-p)/n)1/2 =0.0483
and for 99% CI, z=2.5758
hence confidence interval =P+/- z*std error =0.1756 ; 0.4244
X 1.000 3.000 2.000 4.000 0.000 2.000 1.000 2.000 mean(X) 1.875 std deviation(S) 1.246 std error =S/(n)1/2 0.441Related Questions
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