2017AP Statistics Summer Packet.pdf

# The variance 2 s of a set of observations in the

This preview shows pages 12–17. Sign up to view the full content.

The variance 2 s of a set of observations in the standard deviation squared, meaning the average of the squares of the deviation of the observations from their mean.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
13 Example: Below is a list of test scores earned by AP Statistics students on the chapter 1 test. Find the mean and standard deviation. 88 72 96 68 81 1. Find the sample mean: 8 8 7 2 9 6 6 8 8 1 8 1 5 x 2. i x i x x 2 i x x 88 88 81 = 7 (7) 2 = 49 72 72 81 = -9 (-9) 2 = 81 96 96 81 = 15 (15) 2 = 225 68 68 81 = -13 (-13) 2 = 169 81 81 81 = 0 (0) 2 = 0 1. 2 i x x = 49 + 81 + 225 + 169 + 0 = 524 2. 2 5 2 4 5 2 4 1 3 1 1 5 1 4 i x x n . This is the variance! 3. 2 131 11.45 1 i x x n . This is the standard deviation.
14 Example Problem: TI 83/84 Calculator Instructions: Your calculator will compute the mean, standard deviation, and five number summary for you. 1. Press the STAT button on your calculator. #1 will be highlighted. Press ENTER. 2. Enter the data into L 1 . 3. Press 2 nd MODE (Quit) to exit the screen. 4. Press STAT, then move the cursor to the right so CALC is highlighted. #1 should be selected. Press ENTER. 5. The screen of your calculator will say 1-Var Stats. Type in L 1 (since your data is in List 1) ENTER. 6. The sample mean, x , is the first value given. Sx is the sample standard deviation. Scroll down to find the five number summary. Now, complete Worksheet C (Center, Spread, and 5-Number Summary); page 31

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document