A stock analyst wants to determine whether there is a difference in the mean rate of return for three types of stock: utility, retail, and banking stocks. The following output is obtained: Analysis of Variance Source DF SS MS F P Factor 2 86.49 43.25 13.09 0.001 Error 13 42.95 3.30 Total 15 129.44 Level N Mean St. Dev ---------+------------+-------------+-------- Utility 5 17.400 1.916 (------*--------) Retail 5 11.620 0.356 (------*--------) Banking 6 15.400 2.356 (------*-------) Pooled st dev = 1.818 ---------+------------+-------------+-------- Find the 95% confidence interval for the difference between the mean rates of return for the utility and the retail stocks. (Round your answers to 2 decimal places.) 95% confidence interval is: ____ Solution A stock analyst wants to determine whether there is a difference in the mean rate of return for three types of stock: utility, retail, and banking stocks. The following output is obtained: Analysis of Variance Source DF SS MS F P Factor 2 86.49 43.25 13.09 0.001 Error 13 42.95 3.30 Total 15 129.44 Level N Mean St. Dev ---------+------------+-------------+-------- Utility 5 17.400 1.916 (------*--------) Retail 5 11.620 0.356 (------*--------) Banking 6 15.400 2.356 (------*-------) Pooled st dev = 1.818 ---------+------------+-------------+-------- Find the 95% confidence interval for the difference between the mean rates of return for the utility and the retail stocks. (Round your answers to 2 decimal places.) 95% confidence interval is: ____ ± ________ SOURCE DF SS MS F TREATMENT A 86.49 B C ERROR 13 42.93 3.30 D E STOCK TYPR N MEAN SD UTILITY 5 17.40 1.916 BANKING F 11.62 0.356 6 15.40 G A=2 B=43.25 C=13.09 D=15 E=129.44 F=5 F= 13.09 ,critical value is f(2,13)=3.81 =>reject null Means ALL MEANS ARE EQUAL MANY WAYS -DIFFEENCE IN MEANS TS=(5.78)/0.674= 8.578 UTILITY 15.6862775 17.40 19.1137 REALITY 11.30 11.62 11.93 SOURCE DF SS MS F TREATMENT A 86.49 B C ERROR 13 42.93 3.30 D E.