Lecture 2 Biology & Engineering Approaches PDF

Biology & Engineering Approaches Module: 1 Dr. Priyanka Singh Department of Bioscience & Bioengineering, IITJ  Scientific Method: detailed, empirical problem-solving process used by...

Biology & Engineering Approaches Module: 1 Dr. Priyanka Singh Department of Bioscience & Bioengineering, IITJ  Scientific Method: detailed, empirical problem-solving process used by biologists and other scientists https://app.jove.com/science-education/v/10649/scientific-method-observation-hypothesis-and-experiment  What is a hypothesis? Hypothesis: A hypothesis is a testable statement that predicts the relationships between variables. It is based on existing theories and knowledge and serves as a foundation for testing and validation through scientific methods. Prediction: statement about cause & effect Assumption: Already known property that may provide framework for hypothesis testing Example: Red roses & Honeybee Hypothesis: Red roses attract honeybees. Prediction: if twice the number of roses, then there will be twice the number of honeybees. Assumption: Honeybees are attracted to all sizes of rose or all hues of red equally. https://app.jove.com/science-education/v/13608/what-is-a-hypothesis  Example: Slug and cabbage 1) Observation: Slugs destroy some cabbages but not those near garlic plants 2) Questions: Could garlic be used to deter slugs from ruining cabbages? 3) Develop Hypothesis: Garlic deter slugs. 4) Prediction: Cabbages surrounded by garlic powder will suffer less damage than the ones without 5) Design experiment: Define variables: Independent variable: Item tested (garlic powder) Dependent: Measurement used to determine the outcome (no. of slugs on the cabbage) Set up Groups: identical except for independent variable Experimental: exposed to garlic Control: not exposed to garlic 6) Data collection & Analysis: 7) Conclusion: If the results of an experiment support the hypothesis, further experiments may be designed and carried out to provide support for the hypothesis. The hypothesis may also be refined and made more specific. For example, additional experiments could determine whether slugs also have an aversion to other plants of the Allium genus, like onions. Reasoning to generate & test hypothesis  Deductive Inductive Abductive Top-down Bottom-up Best explanation Incomplete Specific Use general rule to observation used observation drive reach to specific to provide most general conclusion plausible principle/rule explanation Certainty in conclusion; Links Probable Everyday problem evidence to conclusion solving conclusion Crow is a bird that can fly (evidence 1) Grass is wet (incomplete observation) All Chinese like rice (major premise or major evidence) Dove is a bird that can fly (evidence 2) Mr. Lee is Chinese (sub-premise) Parrot is bird that can fly (evidence 3) Conclusion: It probably rained (though other Sparrow is a bird that can fly (evidence 4) explanation possible) Conclusion: Mr. Lee like rice Conclusion: All birds can fly  Hypothesis Testing A statistician will decide using statistical tests about the claims that proceed the hypothesis statements. This process is called "hypothesis testing." A hypothesis test involves collecting data from a sample and evaluating the data. Then, the statistician decides whether there is sufficient evidence, based upon analyses of the data, to reject the null hypothesis. Null & Alternate Hypothesis: https://app.jove.com/science-education/v/13609/null-and-alternative-hypotheses Hypothesis tests: right-tailed, left-tailed, and two-tailed. https://app.jove.com/science-education/v/13612/types-of-hypothesis-testing Incorrect hypothesis: if something happens by chance or its occurrence is infinitely small (probability of occurrence) Example (Red roses & honeybees): Honeybees are attracted to red cans