1. Revision Questions Experimentation

2. 2 Explain Independent variable The variable that is changed by the person doing the experiment. Remember: If I am doing the experiment then I change the Independent variable

3. 3 Explain Dependent variable This is what changes in response to the changing of the independent variable.

4. 4 What is a control or control group? Experiment(s) that are subjected to normal conditions. You usually know how these are going to react.

5. 5 1. Plan and design the experiment 2. Be aware of Safety procedures 3. Select organisms at random 4. Use a large enough sample size 5. Use a control group 6. Use Double-blind testing 7. Change one factor at a time 8. Measure changes 9. Analyze the results 10. State possible sources of error 11. Repeat the experiment How would you organise an experiment?

6. 6 What is double-blind tresting? During trials to examine the effectiveness of a new pill, two sample groups are taken. One group gets the pill under test and the other a placebo. All pills are the same size, colour, taste, etc., but coded differently. When the trials are over, it is possible to distinguish between the control and experimental groups. This ‘ double-blind ’ testing method avoids bias during the trials.

7. 7 END