Scientific Method

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					          SCIENTIFIC METHOD


CSC 426
Ali
              OVERVIEW
DEFINITION OF SCIENTIFIC METHOD
SOLUTION PROCESS
   PHASE 1
        PROBLEM STATEMENT
        BACKGROUND CHECK
   PHASE 2
        SCIENTIFIC METHOD APPLIED
   PHASE 3
        REPLICATION AND PEER REVIEW
        UNINTENDED CONSEQUENCES
 DEFINITION OF SCIENTIFIC METHOD

The scientific method:
• Applies to a measurable problem
• is a step-by-step procedure to solve a stated
  problem through experiments or observation
• Outlines a set of requirements at every step
• Does not allow shortcuts in the main steps.
       Forms of scientific method

• The scientific method can be based on inductive
  reasoning or deductive reasoning. [1]
• Inductive reasoning. Reasoning from the
  particular to the general.
  – Based on experiments. Better suited for physical
    sciences. Causal action [Most used]
  – Based on observation/interviews. Better suited for
    Anthropology, Astronomy, etc.. Descriptive
• Deductive reasoning. Reasoning from the general
  to the particular.
    Phase 1 – PROBLEM STATEMENT

The problem should be:
• Measurable (submits to the scientific method)
• Clearly and concisely stated
• If necessary, divided into simpler measurable
  components
      Problem Statement - Examples
Category               Problem
General                Negative impact of drug-related wars on populations
Specific               Drug-related deaths in Juarez, Mexico, in 2009 [2]
General                ADD in teens
Specific (Fictional)   ADD in teens who do not participate in athletic activities
                       for more than one hour/week
General                Big bang scientific controversies
Specific               Failure of the big bang theory to account for the
                       homogeneity of the cosmic microwave background (CMB)
                       radiation [3]
  Problem Statement – Questions
Steps to refine a problem:
• Benefits (immediate, long-term, etc.)
• Timeline (when did the problem happen?)
• Localization (narrow the scope of problem)
• Population (focus on specific groups)
• Urgency (deadline to solve a problem)
         Background Research
Once the problem has been adequately stated,
• Do background research on the problem:
  – potential solutions may already exist
  – Helpful discussions or hypotheses may exist
• If the problem has been solved, move on!
• Else, revise the problem or select a new one.
 Problem Statement - Summary

                        Problem
                       Statement


Background work

                        Problem    Yes
                        Already
   No                   Solved?


   Scientific Method
   Phase 2 - SCIENTIFIC METHOD
The scientific method is a tool to solve the
  stated problem
• It is composed of four steps in order:
  – Formulation of a hypothesis.
  – Conducting experiments or making observations.
  – Testing resulting data.
  – Reaching a conclusion.
       Formulating a Hypothesis –
         General Requirements
A hypothesis is an educated guess about solving
  the stated problem.
Requirements:
• Specific to the problem
• Clearly stated (preferably as a statement)
• Testable
• Refutable
• Verifiable (directly or indirectly)
  Formulating a Hypothesis – Examples
Problem                                     Hypothesis
Drug-related deaths in Juarez, Mexico, in   Stop weapons and money illegally
2009                                        imported from U.S.

ADD in teens who do not participate in      Use drugs D1 and D2, alone or in
athletic activities for more than one       combination to eliminate deficit
hour/week
(Fictional problem)                         (Fictional drugs)
Failure of the big bang theory to account   Inflation, hundredths of a second prior to
for the homogeneity of the cosmic           big bang, spread elements all over at
microwave background (CMB) radiation        speeds higher than speed of light
                                            (Inflationary hypothesis)
         Testing Your Hypothesis –
          General Requirements
• Hypothesis is tested through experiments and
  observation
• Experiments and observation must be related to the
  hypothesis
• Relationships: cause-and-effect or correlations
• Tools must be readily available
• All experiments, observations and results recorded
• No bias. Do not favor supporting data
• Do not use outside elements (politics,…) to force
  acceptance of hypothesis.
                     Hypothesis Testing –
                    Specific Requirements
Induction                                                  Deduction
Experiments                           Observation          Indirect observation
• Determination of target             • Reliable           • Indirectly tested
population
• Baseline assessment
• Randomization – random              • Repeated           • Mathematical calculations
assignment of subjects to                                  validated
experimental/control groups
• Planned [design of experiment]      • Passive observer
  - Proof by [validity/reliability]
• Replicable contradiction (null      • Reproducible
hypothesis)
• Ethical
• Replicable [validity/reliability]   • Reproducible
• Ethical
                     Hypothesis Testing –
                         Examples
Induction                                         Deduction
ADD Drugs Hypothesis       Juarez Hypothesis      Inflation hypothesis
[Experimental]             [Descriptive]          [Indirect observation]
• Set baseline based on    • Trace weapon origin • Measure non-uniformities using
information from                                 probes
subjects                                            - COBE (1992)
                                                    - WMAP (2003)
• Create 1 control and 3   • Trace money to its
experimental groups        source
• Apply tests to groups    • Collect/study
                           bullets from victims
• Document process         • Document process     • Document process
• Replicate tests
                Data analysis

• Measurements resulting from experiments
  and observations should be collected,
  analyzed and documented
• Resulting data should be used to validate or
  falsify hypothesis
• If a hypothesis is refuted (null hypothesis
  succeeds), a new hypothesis should be
  constructed and the process restarted.
             Data Analysis – Examples
Induction                                          Deduction
ADD Drugs             Juarez Hypothesis            Inflation hypothesis
Hypothesis
• Test results        • Against Hypothesis         • Hypothesis on predicted non-
inconclusive [Null        - Most weapons come      uniformities validated by:
hypothesis was not    from Central and South          - Probe Cosmic Background
rejected – type I     America (NRA)                Explorer (COBE) in 1992
error?]                  - Weapons to Cartel are      - Probe Wilkinson
                      provided by corrupt police   Microwave Anistropy Probe
                      and military                 (WMAP) in 2003

Null hypothesis not   • In favor of                Hypothesis accepted!
rejected!                - Investigations from
                      Mexico are validated
                         - U.S. government
                      implicitly agrees
                Final Phase
• Unsolicited replication of experiments
• Peer review
  Scientific Method- Summary
                     Problem Statement



                         Problem          Yes
                         Already
    No                   Solved?
Provide Hypothesis                              No
Check Hypothesis              No
                            Conclusive?         Test again
   Test Results
                             Yes
                             Publish!           Yes
Thank You!
                             References
[1] Jere H. Lipps. http://palaeo-electronica.org/2000_2/editor/jere.htm
Department of Integrative Biology and Museum of Paleontology, University of
    California, Berkeley, CA 94720, USA. Nov. 2000

*2+ CBS’ Face the Nation. http://www.msnbc.msn.com/id/30179854/
    Mexico: Weapons from U.S. fuel drug war. Associated Press, April 12, 2009

[3] Brad Lemley. Guth's Grand Guess.
    http://discovermagazine.com/2002/apr/cover/?searchterm=Guth%27s%20Gran
    d%20Guess. April 1, 2002

[3] ALAN H. GUTH, Victor F. Weisskopf Professor of Physics.
    http://web.mit.edu/physics/facultyandstaff/faculty/alan_guth.html

CSC426 Class Material.