CW #5 Two Sample Proportions copy

Office 1 Office 2 No No No No No No No No No No Yes No No No No No No No No No No No I am 90% confident that the true proportion of error rate for office one No No No No No No No No No Yes Yes No No No Yes No No Yes No Yes Office 1 Office 2 No No 35 27 Reject the null. There is sufficient ev No No 250 300 No Yes No No No No No No No No No No No No No No No No Yes No No No No No No No No Yes No No No No No No No No A tax preparation firm is interested in comparing the qu work at two of its regional offices. By randomly selecting samples of tax returns prepared at each office and verif sample returns’ accuracy, the firm will be able to estima proportion of erroneous returns prepared at each office Calculate a 90% confidence interval for the difference b population proportions. Interpret. Perform the correct hypothesis test at the 0.1 level of significance to see if there is a difference in error rates b the two offices. Is the hypothesis test consistent with the confidence int Explain.

No No No No No No No No No No No No No Yes No No No No No No No No No No No No No No No No No No No No No No Yes No Yes No No No Yes Yes No No No No No No Yes No No No No No No No No No No No No No No Yes No No No No No No Yes No No No No No No No No Yes No No No No

No No No No No No No No No No No No Yes No Yes No No No No Yes No No Yes No No No No No No No No No No No Yes No No Yes No No No No No No No No No No No No No No No No No No No No No No No No No No No No Yes No No No No No No No No No No No No No No No No No No No

Yes No No No No No No Yes No No No No Yes No No Yes No No Yes Yes No No No No No No No No No No No No No No No No Yes No No No No No No Yes No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No Yes No No No Yes No No No No No No No

No Yes No No No No No No No No No Yes No No No No No No No No No No No No No No No No No No No Yes No No No No No No No No No Yes No

No

Two-Sample Proportions Confidence Interval x1 35 x2 27 p-bar1 0.14 pooled p n1 250 n2 300 p-bar2 0.09 pooled q p-bar1 0.14 p-bar2 0.09 OR q-bar1 0.86 q-bar1 0.86 q-bar2 0.91 q-bar2 0.91 se CL 0.9 CL 0.9 alpha 0.1 alpha 0.1 alpha/2 0.05 alpha/2 0.05 z-stat p-value z-critical 1.65 z-critical 1.644854 *Note this form se 0.02747 se 0.02747 Left Tailed Right Tailed ME 0.045188 ME 0.045184 Two-Tailed LCL 0.004812 LCL 0.004816 UCL 0.095188 UCL 0.095184 Input Information

Hypothesis Test 0.1127272727 0.112727 0.8872727273 OR 0.887273 0.0270828135 0.027083 1.8461892806 1.846189 0.0648647269 mula will change depending on left-sided, right-sided, or two-tailed. use Norm.S.Dist() use 1-Norm.S.Dist() if test statistic is negative, use 2*Norm.S.Dist() if test statistic is positive, use 2*(1-Norm.S.Dist())