8.14.2013 Measures of Center

Do Now Find the mean, median, and mode for this data set. {10, 2,15, 4, 2, 6, 2, 10, 5, 4}

Objective and Agenda - Example I can calculate the mean, median, and mode of a data set, noting outliers. Agenda Class problem (20) Class Independent Practice (15) Independent Closure/Exit Ticket (10) Independent

Class Problem Adam scored 88, 92, 85,65, and 89 on five tests in his history class. Each test was worth 100 points. Adam’s teacher usually uses the mean to calculate each student’s overall score. How might Adam argue that the median is a better measure of center for his test scores?

First Find the mean: Add all of Adam’s test scores to find the sum 88+92+85+65+89 = 419 Then divide the sum by 5 because there are 5 test scores 419/5 = 83.8

Adam’s teacher uses the mean, but does this represent how Adam does on his tests? Compare Adam’s test scores with the mean. All of his test scores are higher than the mean. Maybe he could justify to his teacher that the median is a better representation of his grade.

Does this seem to be a better fit with his scores? I think so. Find the median Put them in order from lowest to highest and pick the center data point. 65, 85, 88, 89, 92 median = 88 Does this seem to be a better fit with his scores? I think so.

Adam could go to his teacher a say, “The test score of 65 is an outlier and is not a typical test score for me. One outlier can really skew the mean. The median test score of 88 better represents how I typically do on tests.”

Independent Practice (silent and on your own, if you have a question ask me, your neighbor is busy working) Complete the following 1a, 1b, 2a, 6

Exit Ticket List the steps for finding the median of a data set. List the steps for finding the mean of a data set. List the steps for finding the mode of a data set.