# IM3.7B.3 MOE

The pdf below contains 100 rectangles of various areas. To select a random sample of 10 rectangles, we're going to use a spreadsheet function to generate lists of random numbers, then find the areas of those rectangles, then calculate the mean area of our sample.
1. In cell A1, type

**=randombetween(0,99)**and press**return**2. Hold your cursor over the square in the bottom right corner of this cell to get the**+**cursor, then drag down to cell A10. You should now have a list of 10 random numbers between 0 and 99. Find the areas of those rectangles and list them in column B.1. Calculate the mean and **sample** standard deviation (s, not σ) of the areas by selecting column B and choosing 1 variable analysis, then show statistics.
2. Use the sample standard deviation to estimate the population standard deviation using this formula:
3. Use this estimate to estimate the margin of error for your sample (2 standard deviations).
4. Report: What does this MOE tell you?