# Testing 1,2,3

## Objective

SWBAT apply the student t-test appropriately given data sets

#### Big Idea

Are Bounty Paper Towels really the best? Let your students find out for themselves while they learn to use the t-test.

## Set the Stage

10 minutes

To begin this lesson I show my students a Bounty(TM) commercial and have them select characteristics we can test in the classroom to prove or disprove the product claims in the commercial.  My testing 1-2-3 video narrative explains most of this process while this written narrative section provides some additional insights and suggestions.  First, be sure that you have materials on hand for this activity including at least two or three brands of paper towels, something to test strength (marbles or pennies work well) and something to test volume of water held (small water bottles and the smallest size dixie cup available, marked on the outside to ensure equal volumes for each test, work well)  Second, your students will probably need some help setting up their testing protocols. I find it easiest to work through this as a class to make sure all the data is collected in the same manner.  Finally, even if the t-test clearly demonstrates that there is NOT a statistically significant difference, you will probably have at least a few students who will insist that the towel that held more pennies, or water, or whatever you measured is actually better.  For those kids I usually come back to the idea that we only ran a few tests on one batch of towels which is kind of like flipping a coin three times and deciding it's unfair if it comes up heads all three times.  I remind them that during another series of coin flips we might get tails three times in a row and that another set of tests with the paper towels might have the "losing" brand doing better.  I've also included a video of how to use a TI 84 calculator for a t-test.

## Put it into Action

45 minutes

For this section you will need materials for measuring and at least three brands of paper towels, including Bounty.  You will also want copies of the "Additional Data Sets" handout and the"Bounty Dilemma" handout.

Teamwork 15 minutes: I start by distributing the Bounty Dilemma handout and asking my students to read through it and ask any questions they may have.  I then have  them get all their materials including measuring tools and let them collect data. (MP1) This usually takes about 15 min and during this time I walk around offering encouragement and redirection as needed.  As teams finish collecting data I have them post their results on a chart I've created on the board.  (You will need to make a row for each measurement you've chosen and a column for each brand of paper towel you are testing)  I ask my students that they should each be recording the class data on their papers because they will be working independently for the calculations portion of this activity.  I also remind them that they need to return all materials to the appropriate places and clean up their area if necessary.

Independent Practice 10 minutes: When all teams have posted their data I tell my students that they will be working independently for the next section of the lesson and encourage them to finish copying the class data if they haven't already done that.  I then tell them to find the mean and standard deviation for each set of data and record it on their paper.  Some students will enter the data into a STAT list while others will begin to add all the values in the home screen. (MP5)  I have found that those students who are not using the STAT options are generally not comfortable with them and need additional support to be successful with this tool.  While it is certainly acceptable to find mean and standard deviation without using a graphing calculator, it is much more time consuming and cumbersome, so I really try to help my students learn when to use this tool as much as how to use it.  As they're calculating, I walk around to assist students who need assistance.  I also encourage them to answer question 5 on their handout, predicting whether there are any statistically significant differences in the measurements for the different paper towel brands.  We've covered significance in an earlier lesson, so this should be review for my students.