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Day 2: The Scientific Method and Critical Thinking. Instructor Name firstname.lastname@mail.wvu.edu August 20, 2008. The Scientific Method. Problem Solving. Problem solving is the process of analyzing and finding solutions for questions that we want to solve.
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Day 2:The Scientific Methodand Critical Thinking Instructor Namefirstname.lastname@mail.wvu.edu August 20, 2008
Problem Solving • Problem solving is the process of analyzing and finding solutions for questions that we want to solve. • How do we perform problem solving? • One way is with the scientific method, the process by which scientists, collectively over time, endeavor to construct an accurate representation of the world.
Scientific Method • 4 major components • Observation • Hypothesis • Prediction • Experiment • 1 evaluation step • Decision
Scientific Method Process theory If everything is consistent, advance hypothesis into theory. Consistent observation hypothesis predictions Inconsistent, edit hypothesis If not consistent, modify predictions and test again. tests
Observation • Areas of interest in which one sets out to prove truth or faults. • What kind of observations can you think of? • The average temperature of the earth is rising. • Foreign-made cars have been gaining market share in the United States. • People from the southern US tend to be more tanned than those in the northern part of the US.
Observation In-Class Example • An example of an observation might be: • You work for a computer manufacturer. The latest model, the X900, is selling very well. • You wish to explore this observation and find out the reason for the strong sales.
Hypothesis • Suggested explanation of problem or observation • How do we get hypotheses? • From other branches of science • Informed guesses • Random ideas
Hypothesis In-Class Example • What hypotheses might explain the sales of the X900? • Looking at marketing data per year, the amount spent on Internet advertising appears to be higher the year this computer was introduced. • Hypothesis: the increased sales were the result of the increase in Internet advertising. • This computer was the first to use the latest graphics card, the Screamer 9200. • Hypothesis: the increased sales were the result of using the latest graphics card.
Prediction • Formal way to put a hypothesis to the test. • If the hypothesis is true, when x is manipulated, then yshould happen. • xis the independent variable: it's the thing changed. • yis the dependent variable: its value depends on x.
Prediction In-Class Example • What predictions could you make based on the data we have? • If a greater amount is spent on Internet advertising, computers will sell better. • Using the latest components will increase sales.
Experiment • Test hypothesis to see if it’s correct. • Lab experiment (grow cultures in petri dish) • Analyze current data using computer applications (Access, Excel) • First hypothesis may not be correct • If so, no problem: go back and change it • May not be possible to completely prove or disprove a hypothesis • Example: Can’t completely prove or disprove whether cell phones cause driving accidents • What do we do in that situation?
Experiment In-Class Example • What can we do with our data to test the hypotheses? • Graphics card hypothesis • Run a query on the components table. Group the data by graphics card type. Do the units sold tend to be higher for certain cards? • Export this data into Excel and graph it, with units sold on the y axis, and the component name on the x axis, for each component type. Is there a pattern? • Internet advertising hypothesis • Run different sorts, by each advertising type, then by year. Does there seem to be a pattern? • Export this data into Excel. Graph each expenditure type on the y axis, and the year on the x-axis. Fit a trendline to the data, and forecast it out a few years. Is a pattern visible now?
Decision • Reject or accept the prediction(s). • If the hypothesis appears correct, you can create a new hypothesis, and begin again. • Would this hypothesis apply to other, similar cases? • If it seems incorrect, reformulate and try again. • Remember correlation doesn’t equal causality! • When the sun rises, the sky gets light. Does sunrise cause a blue sky? Yes! • People who don’t wear seat belts tend to have worse accidents. Does one cause the other? Only partially! • Tall people usually weigh more. Does height cause weight? No! • In each case, though the first and second are related, it’s not necessarily true that one causes the other.
Decision In-Class Example • A sharp increase in the percentage of Internet advertising the year the X900 was introduced was the reason for its increase in sales. • Look at other computers introduced that year to get a better idea if this is correlation or causality. • The use of the Screamer 9200 was the reason for the X900’s success. • Again, correlation vs. causality: check out other computers that use the new card to see which one is the case.
Critical Thinking • Definitions: • The scientific method applied to life. • An attempt at objective judgment so as to determine both merits and faults. • The art of taking charge of your own mind!
Non-critical Thinking • Left to our own devices, our thinking often uses rigidity, over-generalization, prejudice, and common fallacies. • Voting a certain way because that's the way your parents did (or didn't!) • Buying a brand new car because it looked good on the lot. • Copying/pasting in Word using a mouse because that's the way you've always done it.
Why use it? • Objectively arriving at a decision (the purpose of critical thinking) has many benefits. • Cheaper (you’ll buy less frivolous/needlessly expensive things) • Healthier (more likely to exercise, spot doctor mistakes) • Better grades (critical thinking = better study habits!) • Higher pay (critical thinking is invaluable in finding and keeping a great job)
Critical Thinking in CS101 • Is there a faster way to do the task I’m doing than the way I already knew? • Shortcut keys, icons, etc. • How do I use Microsoft Office to answer the critical thinking questions? • Access: sorting/grouping with queries • Excel: graphing, scenarios, PivotTables • PowerPoint: organizing ideas effectively • Word: getting ideas down on paper makes them clearer
Critical Thinking in School • When studying, turn section titles into questions, and use that section’s text as a chance to answer that question • If the section is titled “Formatting Spreadsheets in Excel, ask yourself “How do I format spreadsheets?”, and look for the answers as you read. • Do extra review questions at the end of chapters. • At the end of each lecture, take one minute, and answer the following (try this now!) • What’s the most important thing I learned today? • What’s the thing I’m still most confused about?
Critical Thinking in Life • When trying to decide whether to buy something • Do I really want/need it? • Can I afford it? • Is it good (healthy, non-dangerous) for me? • When voting • Familiarize yourself with the issues. • Think about the long-term implications of your choice. • At the doctor • Ask questions. • Get a second opinion.