How profitable are different sectors of the stock market One way to answer such a question is to examine profit as a percentage of stockholder equity A random sample of 32 retail stocks such as Toys R Us Best Buy and Gap was studied for x profit as a percentage of stockholder equity The result was x 14 7 A random sample of 35 utility gas and electric stocks such as Boston Edison Wisconsin Energy and Texas Utilities was studied for x2 profit as a percentage of stockholder equity The result was x 11 1 Assume that o 3 1 and 3 7 a Let represent the population mean profit a percentage of stockholder equity for retail stocks and let represent the population mean profit as a percentage of stockholder equity for utility stocks Find a 95 confidence interval for Round your answers to two decimal places lower limit upper limit b Examine the confidence interval and explain what it means in the context of this problem Does the interval consist of numbers that are all positive all negative of different signs At the 95 level of confidence does it appear that the profit as a percentage of stockholder equity for retail stocks is higher than that for utility stocks Because the interval contains only positive numbers we can say that the profit as a percentage of stockholder equity is higher for retail stocks