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Unformatted text preview: AI-1Appendix IThe Scientific Method The study of science is different from other disciplines in many ways. Perhaps the most important aspect of “hard” science is its adherence to the principle of the scientific method: the posing of questions and the use of rigorous methods to answer those questions. I. Our Friend, the Null HypothesisAs a science major, you are probably no stranger to curiosity. It is the beginning of all scientific discovery. As you walk through the campus arboretum, you might wonder, “Why are trees green?” As you observe your peers in social groups at the cafeteria, you might ask yourself, “What subtle kinds of body language are those people using to communicate?” As you read an article about a new drug which promises to be an effective treatment for male pattern baldness, you think, “But how do they know it will work?” Asking such questions is the first step towardshypothesis formation. A scientific investigator does not begin the study of a biological phenomenon in a vacuum. If an investigator observes something interesting, s/he first asks a question about it, and then uses inductive reasoning(from the specific to the general) to generate an hypothesisbased upon a logical set of expectations. To test the hypothesis, the investigator systematically collects data, either with field observations or a series of carefully designed experiments. By analyzing the data, the investigator uses deductive reasoning(from the general to the specific) to state a second hypothesis (it may be the same as or different from the original) about the observations. Further experiments and observations either refute or support this second hypothesis, and if enough data exist, the hypothesis may eventually become a theory, or generally accepted scientific principle. Proper scientific method requires that the investigator state his/her hypothesis in negative terms, forming a null hypothesis(Ho)concerning the expected results of the study. The null hypothesis states the expected results by predicting that there will be no difference between the test groups. For example, if a pharmaceutical company is attempting to test a new weight loss drug (Fat-B-Gontm), its scientific investigators might put forth a null hypothesis stating: "There is no differencein the rate of weight loss between members of the population who use Fat-B-Gontmand those who do not use Fat-B-Gontm" A second hypothesis, the alternative hypothesis (Ha), states the exact opposite of the null hypothesis. Hais, of course, the hypothesis of interest: "There is a differencein the rate of weight loss between members of the population who use Fat-B-Gontmand those who do not use Fat-B-Gontm." By stating the question as a null hypothesis, the investigator allows much less ambiguity in accepting or rejecting one or the other hypothesis. Once the null hypothesis is rejected, the alternative hypothesis becomes subject to greater scrutiny and further testing....
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This lab report was uploaded on 04/18/2008 for the course BIL 161 taught by Professor Krempels during the Spring '08 term at University of Miami.
- Spring '08