## Question

###### How profitable are different sectors of the stock market? One way to answer such question to examine profit as percentage of stockholder equity random sample of 35 retail stocks such as Toys 'R Best Buy, and Gap was studied for X1, profit as percentage of stockholder equity: The result as 13.6. random sample of 36 utility (gas ad electric) stocks such Boston Edison_ Wisconsin Energy, and Texas Utilities was studied for Xz, profit as percentage of stockholder equity. The result was Xz 9.3. A

How profitable are different sectors of the stock market? One way to answer such question to examine profit as percentage of stockholder equity random sample of 35 retail stocks such as Toys 'R Best Buy, and Gap was studied for X1, profit as percentage of stockholder equity: The result as 13.6. random sample of 36 utility (gas ad electric) stocks such Boston Edison_ Wisconsin Energy, and Texas Utilities was studied for Xz, profit as percentage of stockholder equity. The result was Xz 9.3. Assume that 01 3.1 and 02 3.2. Categorize the problem below according to parameter being estimated, proportion mean /, difference of means /l1 H2, Or difference of proportions P1 Pz . Then solve the problem: (b) Let /i represent the population mean profit as percentage of stockholder equity for retail stocks, and let /2 represent the population mean profit as percentage of stockholder equity for utility stocks_ Find 95% confidence interval for 41 Hz. (Use decimal place. Lnerunutl (c) Examine the confidence interva and explain what 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%0 level of confidence, does it appear that the profit as percentage of stockholder equity for retail stocks higher than that for utility stocks? Because the interva contains only positive numbers, we can say that the profit as percentage stockholder equity is higher for retail stocks Because the interval contains both positive and negative numbers_ we can not say that the profit as percentage of stockholder equity is higher for retail stocks: We can not make any conclusions using this confidence interval: Because the interval contains only negative numbers we can Say that the profit as percentage of stockholder equity higher for utility stocks.