Help on my practice please

I, chrome File Edit View History Bookmarks People Tab Window Help MyOpenMath X c * myopenmath.com I; Q smil- Thu11:54AM Q (:9 SE Recently, the Derma#1 research clinic published a report stating that the regular application of a very popular sunscreen lotion ContraHelios might cause some forms of skin cancer. The manufacturer of ContraHelios issued an energetic counterstatement asserting that the Derma#1 clinic's conclusions were statistically inconsistent. Take Care pharmacy chain has been selling ContraHelios lotion for a long time. The market research department of Take Care wants to see what is currently happening with ContraHelios lotion demand. The members of a random sample of customers were asked about their willingness to use ContraHelios before and after the publication of Derma#1 clinic's report. The answers were provided in form of a score from O to 10 (higher score means more willingness). Results for five customers are shown in the following table. The "before" score is matched to the "after" score, and the difference should be calculated. Suppose that it is known that such differences have approximately bell-shaped distribution. Pan: I, Suppose that differences are d = Before After . Find the sample mean J and sample standard deviation 3.1 of the differences. Step 1. Fill in the column "d = Before After " of the table. Then, calculate (i and fill in the cell below the table. Step 2. Using d , fill in the last two columns of the table. Participant Before After 1 6 5 2 8 6 3 5 3 4 7 4 5 4 2 Total Sample mean of the differences is d = G 52mins > Next Question I V