Lesson 3: Measuring Variance and Standard Deviation

August 29, 2018

Review:

• Measures of Center
• Boxplots
• Statistics Add-on issues
• Alternative for boxplots (hat tip to Martin Trujillo): http://www.imathas.com/stattools/boxplot.html
• Attendance

Presentation:

• Variance and Standard Deviation

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  • 

    • 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 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 9th-grade students and six 12th-grade students were asked: how many movies have you seen this month? Here are their responses.
9th-grade: 5, 1, 2, 5, 3, 8
12th-grade: 4, 2, 0, 2, 3, 1

Calculate the mean and standard deviation for each data set. Which is more spread out, the 9th-grade or 12th-grade 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. 40-44