Walmart has collected the retention rates in the first 10 periods in Table 2 (see the Excel file). Suppose the retention rate ceiling is 90% and the cohort size is 2,000. Please fill in the relevant cells from Column 2 to Column 7. How much is the average retention rate? Hong long is the average customer lifetime duration? Please use Excel to solve this problem. Print out your Excel file, and show your answers clearly.

-Please manually calculate the r value for Period 8.

-Suppose the value of r is 0.28. Please manually calculate the projected retention rate in Period 12.

-From your works with Excel, how much is the average retention rate? Hong long is the average customer lifetime duration?