Athlete’s Foot and the Fair Test Stuff in Orange MUST be in your notebook

Background Info Mr. Harris was an awesome athlete in high school. He earned 12 sport letters and started for the varsity team on nearly every sport. Consequently, he spent lots of time in the gym and locker room. He would develop raging athlete’s foot infections – red, itchy, raised bumps all over his toes and feet. Yikes!

The Remedy One time, he was SO sick of itchy feet that he went to the store, spent $40 and bought every product they had for itchy feet: Special shoe insoles Powder for shoes Cream for feet Special infused socks Spray for feet Special ant-fungal soap He used every remedy for 3 days…

The $40 Question After 3 days, his feet were cured – no more red, itchy bumps! After football practice one day, his mom asked, “How are your feet?” He replied that they were fine now. Then she asked, “What did the trick?” What did he reply?

Change only ONE thing at a time Experimental Design He didn’t know what worked to kill his fungal infection because he tested too many cures at once. He did NOT use a fair test method. What SHOULD he have done? Change only ONE thing at a time

Take #2 The next time his athlete’s foot problem flared up, he knew what to do. He focused on just one cure. He decided to try rubbing antifungal cream onto the red bumps. He faithfully applied the cream twice per day to both feet. After 3 days, he was cured! Did he use a fair testing method this time?

Experimental Design Compare two groups In a good experiment, we always compare two or more groups. A “control group” is the name we give to this set of trials which are used as a baseline or a comparison. Most experiments have a control group, but not all. Compare two groups

Take #3 This time, he was sure he knew what to do when the old red, itchy bumps came back. He used one foot as the control group, and did not put any “remedies” on that foot. On the other foot, he tested only one remedy at a time. What does he know about the remedy if… If both feet are still red? If both feet are cured? If the control foot is red and the remedy foot is cleared?

Repeat at least three times Experimental Design If one application of Tinactin cream cures the spots on one foot, can we declare to the world that, “Tinactin cream is the best Athlete’s Foot remedy and should be used by all!” ? Do we have any certainty in our results if we conduct only one trial? Do you think that drug manufacturers test their product only one time? Repeat at least three times