Copyright © 2009 Pearson Education, Inc.
© 2013 Pearson Education, Inc.
PowerPoint Lecture prepared by
Jill Feinstein
Rich...
© 2013 Pearson Education, Inc.
1.1 The Process of Science
 Science refers to a body of knowledge
 Science is not a giant...
© 2013 Pearson Education, Inc.
1.1 The Process of Science
The Nature of Hypotheses
 Hypothesis: proposed explanation for ...
© 2013 Pearson Education, Inc.
1.1 The Process of Science
Where do hypotheses come from?
 Both logical and creative influ...
© 2013 Pearson Education, Inc.
1.1 The Process of Science
Scientific Theory
 Powerful, broad explanation of a large set o...
© 2013 Pearson Education, Inc.
1.1 The Process of Science
Steps of the Scientific
Method
 The process looks
something lik...
© 2013 Pearson Education, Inc.
1.1 The Process of Science
© 2013 Pearson Education, Inc.
1.1 The Process of Science
The Logic of Hypothesis Tests
 A hypothesis that fails our test...
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
The Experimental Method
 Experiments are designed to test specific
...
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Controlled Experiments
 Controlled experiment: tests the effect of ...
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Controlled Experiments
 Differences seen between the experimental
g...
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Controlled Experiments
 Example: Echinacea tea experiment:
 Hypoth...
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Controlled Experiments
 People who received
echinacea tea felt that...
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Minimizing Bias in Experimental Design
 If human subjects know whet...
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Minimizing Bias in Experimental Design
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
 The “gold standard” for experimentation
 Double-blind, placebo co...
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Using Correlation to Test Hypotheses
 Using existing data, is there...
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Using Correlation to Test Hypotheses
 Results of such a study: the ...
© 2013 Pearson Education, Inc.
1.2 Hypothesis Testing
Using Correlation to Test Hypotheses
 The correlation might be due ...
© 2013 Pearson Education, Inc.
1.3 Understanding Statistics
Overview: What Statistical Tests Can Tell Us
 Data collected ...
© 2013 Pearson Education, Inc.
1.3 Understanding Statistics
The Problem of Error
 During experimentation researchers need...
© 2013 Pearson Education, Inc.
1.3 Understanding Statistics
What Statistical Tests Cannot Tell Us
 If an experiment was d...
© 2013 Pearson Education, Inc.
1.4 Evaluating Scientific Information
Primary Sources
 Researchers can submit a paper abou...
© 2013 Pearson Education, Inc.
1.4 Evaluating Scientific Information
Information from Anecdotes
 Anecdotal evidence is ba...
© 2013 Pearson Education, Inc.
1.4 Evaluating Scientific Information
Science in the News
© 2013 Pearson Education, Inc.
1.4 Evaluating Scientific Information
Science in the News
 Secondary sources may be missin...
© 2013 Pearson Education, Inc.
1.4 Evaluating Scientific Information
Understanding Science from Secondary Sources
 Use yo...
© 2013 Pearson Education, Inc.
1.5 Is There a Cure for the Common Cold?
 No, but prevention methods are known
 Wash your...
Upcoming SlideShare
Loading in...5
×

Scientific methodpowerpoint

244

Published on

Overview of the scientific method

Published in: Technology, Education
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
244
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
9
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Transcript of "Scientific methodpowerpoint"

  1. 1. Copyright © 2009 Pearson Education, Inc. © 2013 Pearson Education, Inc. PowerPoint Lecture prepared by Jill Feinstein Richland Community College Fourth Edition BIOLOGYScience for Life | with Physiology Colleen Belk • Virginia Borden Maier ChapterChapter 11 Can Science Cure the Common Cold? Introduction to the Scientific Method * Components of this PowerPoint were altered by Lissa Walls to better fit the learning objectives of Integrated Science: The Living World (SCI 106) *
  2. 2. © 2013 Pearson Education, Inc. 1.1 The Process of Science  Science refers to a body of knowledge  Science is not a giant collection of facts to be memorized.  It is important to learn about the process of science called the scientific method.  The scientific method is used to solve problems and answer questions.  Observations  Proposing ideas  Testing ideas  Discarding or modifying ideas based on results
  3. 3. © 2013 Pearson Education, Inc. 1.1 The Process of Science The Nature of Hypotheses  Hypothesis: proposed explanation for a set of observations  Scientific Hypotheses need to be:  Testable –possible to examine the hypothesis through observations  Falsifiable –able to be proven false if it is untrue  Objective – not influenced by personal feelings or opinions  Ethical - moral
  4. 4. © 2013 Pearson Education, Inc. 1.1 The Process of Science Where do hypotheses come from?  Both logical and creative influences are used to develop a hypothesis
  5. 5. © 2013 Pearson Education, Inc. 1.1 The Process of Science Scientific Theory  Powerful, broad explanation of a large set of observations  Based on well supported hypotheses  Supported by research from several different independent sources
  6. 6. © 2013 Pearson Education, Inc. 1.1 The Process of Science Steps of the Scientific Method  The process looks something like this:
  7. 7. © 2013 Pearson Education, Inc. 1.1 The Process of Science
  8. 8. © 2013 Pearson Education, Inc. 1.1 The Process of Science The Logic of Hypothesis Tests  A hypothesis that fails our test is rejected and considered disproven.  A hypothesis that passes is supported, but not proven.  Why not? An alternative hypothesis might be the real explanation.
  9. 9. © 2013 Pearson Education, Inc. 1.2 Hypothesis Testing The Experimental Method  Experiments are designed to test specific hypotheses.  Variables: factors that can change in value under different conditions  Independent variables can be manipulated by the scientist  Dependent variables cannot be changed by the researcher  Standardized variables (aka controlled variables) kept constant so that any difference in outcome is due ONLY to treatment
  10. 10. © 2013 Pearson Education, Inc. 1.2 Hypothesis Testing Controlled Experiments  Controlled experiment: tests the effect of a single variable  Control: a subject (or group) who is not exposed to the experimental treatment but has all other variables the same  Given either no treatment or a placebo
  11. 11. © 2013 Pearson Education, Inc. 1.2 Hypothesis Testing Controlled Experiments  Differences seen between the experimental group and control group can be attributed to the experimental treatment  Random Assignment  An effective way of assigning individuals to groups for testing
  12. 12. © 2013 Pearson Education, Inc. 1.2 Hypothesis Testing Controlled Experiments  Example: Echinacea tea experiment:  Hypothesis: drinking Echinacea tea relieves cold symptoms  Experimental group drinks Echinacea tea 5-6 times daily  Control group drinks “sham” Echinacea tea 5-6 times daily (placebo)  Both groups rated the effectiveness of their treatment on relieving cold symptoms
  13. 13. © 2013 Pearson Education, Inc. 1.2 Hypothesis Testing Controlled Experiments  People who received echinacea tea felt that it was 33% more effective at reducing symptoms
  14. 14. © 2013 Pearson Education, Inc. 1.2 Hypothesis Testing Minimizing Bias in Experimental Design  If human subjects know whether they have received the real treatment or a placebo, they may be biased.  Blind experiment: subjects do not know what kind of treatment they have received  Double blind experiment: the person administering the treatments and the subjects do not know who is in each group until after the experiment is over
  15. 15. © 2013 Pearson Education, Inc. 1.2 Hypothesis Testing Minimizing Bias in Experimental Design
  16. 16. © 2013 Pearson Education, Inc. 1.2 Hypothesis Testing  The “gold standard” for experimentation  Double-blind, placebo controlled, and randomized experiments  Model systems can be used in experiments when it appears too dangerous or unethical to test on humans  examples: mice, rats, dogs and pigs  A correlation can be used to test hypotheses when controlled experiments on humans are impossible to perform
  17. 17. © 2013 Pearson Education, Inc. 1.2 Hypothesis Testing Using Correlation to Test Hypotheses  Using existing data, is there a correlation between variables?  Hypothesis: stress makes people more susceptible to catching a cold  Is there a correlation between stress and the number of colds people have caught?
  18. 18. © 2013 Pearson Education, Inc. 1.2 Hypothesis Testing Using Correlation to Test Hypotheses  Results of such a study: the number of colds increases as stress levels increase  Caution! Correlation does not imply causation!!
  19. 19. © 2013 Pearson Education, Inc. 1.2 Hypothesis Testing Using Correlation to Test Hypotheses  The correlation might be due to other reasons
  20. 20. © 2013 Pearson Education, Inc. 1.3 Understanding Statistics Overview: What Statistical Tests Can Tell Us  Data collected during experimentation should be organized and analyzed using statistical methods  Comparing means (averages) is a common way to compare the data from two groups  Statistical tests will tell us if differences between groups are due to treatment or due to chance  Statistically significant: unlikely the observed difference is due to chance IF experiment was designed and carried out properly  AKA there is a true difference between the two groups/items compared
  21. 21. © 2013 Pearson Education, Inc. 1.3 Understanding Statistics The Problem of Error  During experimentation researchers need to minimize error; errors affect the outcome of experiments  Experimental error: inconsistent or incorrect measurements, poorly functioning equipment, timing errors, confusing instructions to subjects, etc.  Sampling error: estimation error because of surveying a sample of the population rather than the whole population  Sample size: the number of units (people, plants, animals, illnesses) to be tested/surveyed in an experiment  A larger sample size is more true of the population from which the sample was taken
  22. 22. © 2013 Pearson Education, Inc. 1.3 Understanding Statistics What Statistical Tests Cannot Tell Us  If an experiment was designed and carried out properly  If observer error occurred; statistical tests can only evaluate the probability of sampling error  Practical or biological significance of results
  23. 23. © 2013 Pearson Education, Inc. 1.4 Evaluating Scientific Information Primary Sources  Researchers can submit a paper about their experimental methods and results to a professional journal (primary source)  Primary Sources undergo peer review: evaluation of submitted papers by other experts  Secondary sources: books, news reports, the internet, and advertisements
  24. 24. © 2013 Pearson Education, Inc. 1.4 Evaluating Scientific Information Information from Anecdotes  Anecdotal evidence is based on one person’s experience, not on experimental data  Example: a testimonial from a celebrity
  25. 25. © 2013 Pearson Education, Inc. 1.4 Evaluating Scientific Information Science in the News
  26. 26. © 2013 Pearson Education, Inc. 1.4 Evaluating Scientific Information Science in the News  Secondary sources may be missing critical information or report the information incorrectly  Consider the source of media reports  Be careful with the Internet since anyone can post information  Be very cautious about claims made in paid advertisements
  27. 27. © 2013 Pearson Education, Inc. 1.4 Evaluating Scientific Information Understanding Science from Secondary Sources  Use your understanding of the scientific method to evaluate findings stated by secondary sources  News media generally highlight only those science stories that seem newsworthy  They are more likely to report a positive result than a negative one
  28. 28. © 2013 Pearson Education, Inc. 1.5 Is There a Cure for the Common Cold?  No, but prevention methods are known  Wash your hands!  No effect on cold susceptibility:  Vitamin C  Exposure to cold temperatures  Exercise  No vaccine for the common cold
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×