Lesson 3: Measuring Variance and Standard Deviation
August 29, 2018
Review:
 Measures of Center
 Boxplots
 Statistics Addon issues
 Alternative for boxplots (hat tip to Martin Trujillo): http://www.imathas.com/stattools/boxplot.html
 Attendance
Presentation:
 Variance and Standard Deviation

 Demonstrate with Problem 1.53 on p. 42
 Find the variance and the standard deviation for the following (n=10) exam scores: 80 73 92 85 75 98 93 55 80 90
 Video
 Demonstrate with Problem 1.53 on p. 42
 Demonstrate how to calculate in Sheets
Activity:
Problem 1. Below are the number of home runs that Babe Ruth hit in each of his 15 years with the New York Yankees, 1920 – 1934.
54 59 35 41 46 25 47 60 54 46 49 46 41 34 22
Calculate the mean and standard deviation.
Problem 2. Six 9thgrade students and six 12thgrade students were asked: how many movies have you seen this month? Here are their responses.
9thgrade: 5, 1, 2, 5, 3, 8
12thgrade: 4, 2, 0, 2, 3, 1
Calculate the mean and standard deviation for each data set. Which is more spread out, the 9thgrade or 12thgrade data?
Assignment:
 Repeat Problems 1 and 2 (above) using Sheets
 Using the Student Height Data, calculate mean and standard deviation in Sheets
 Text Ch. 1, p. 4044