Research methods Ch 1-2 

critical thinking

• systematically evaluating information to reach conclusions based on the evidence presented
    * steps in critical thinking:
      * (1) what is the claim
      * (2) what is the evidence (if any)
        * personal experience
        * research
      * (3) is the evidence flawed or biased
        * alternative explanation
      * (4) given the evidence, should the claim be rejected or accepted
      * (5) if accepted, what degree of confidence can we have

Benefits of knowing research methods

• in life:
• careers:
    * mental health
    * business
    * politician

“This I believe”

• personal experience (self or others)
    * informal observations (anecdotal evidence)
• systematic observation (research)
• authority
    * qualifications
    * evidence

limits of personal experience

• faulty perception
• faulty memory
• faulty thinking
    * prone to logical fallacies (handout)
    * confirmation bias

other problems with personal experience

• (1) lacks adequate comparison conditions
    * present-present bias (example of confirmation bias)
      * focus on the presence of an event and the presence of an outcome
        * fail to look for the lack of evidence
      * noticing the hits/ignoring the misses
• (2) it is confounded
    * other plausible alternative explanations

science as a way of knowing

empirical research is designed to minimize these biases

• empirical
    * based on systematic observations
      * “systems” minimize bias; rule out alternative explanations
• theory-data cycle
    * theory
      * explanation of how things generally relate (general principles)
        * not about a specific person or situation
    * hypothesis
    * -a testable prediction about how specific things should relate in a specific context given some theory
    * (1) needs to be replicated
    * (2) science cannot “prove” theories
      * why? because we cannot test all possibility
    * data
      * observations

$my children sleep better on nights when they get a bath$

• $is it the bath that is making them sleep better?$
    * $what do they do during the day on bath nights$
    * $what do they eat before bed time on bath nights$
    * $what is differently done on the days/night they get baths$

science as a way of thinking

• qualities of a good theory
    * supported by a large quantity and variety of evidence
    * falsifiable
      * testable claims, thus rejectable
        * the more testable /falsifiable the better
    * parsimonious
      * the simpler (fewer assumptions, etc.) the better
• kinds of research questions
    * basic
      * designed to increase general knowledge
    * translational
      * designed to develop an application
    * applied
      * designed to solve problems in the real world
• results made public
    * to other scientists → conferences, journals
      * peer review process
      * peer input continues after publication science is self-correcting
      * allows for replication
    * to the public → magazine, newspaper, TV, etc.
      * be cautious
        * why?
          * maybe based on weak/flawed evidence
          * journalist may misreport research or modify conclusions
• really good theories, with no valid alternatives, get treated as” facts”
    * Note: science does not provide absolute “truth”
      * even “facts” are always tentative
• reject theories (or claims) when multiple evidence is disconfirming
• \
    * claim→ older adults are more depressed than younger adults

Example: theory of evolution

• supported by a large quantity and variety of evidence

consulting scientific sources

• scientific journals

class notes 1/13/23

consulting scientific sources

• scientific journals

types of scientific articles

• empirical journal article → actual study
    * contains the following sections.
      * introduction
      * methods
      * results
      * discussion
• review journal articles
    * (a) qualitative → summary of empirical studies
    * (b) meta-analysis
      * quantitative → takes raw data from published studies.
      * new statistical analysis to estimate effect size.

journals

• be careful.
    * not all journals are legit.
      * “predatory”
    * if unsure
      * (a) check that it is peer-reviewed
      * (b) check the “impact factor (>1.0)
        * indicates how often its articles get cited
        * how?
          * journals homepage or internet search

how to find scientific sources

• database via library
    * e.g. PsycINFO
      * searches only psy sources
      * indicates peer review
      * many useful tools
• google scholar
    * searches all journals
    * limitations

non-journal, scientific sources

• edited books (handbooks) less rigorous peer review always reviews of research
• academic books
• dissertations
    * new empirical studies or reviews done by P.H.D students
    * not peer-reviewed
    * should not cite
• trade books and magazine articles
    * how to evaluate
      * how much do they cite other research

descriptive statistics

• ways to organize and summarize data
    * frequency histogram
• two main things to represent.
    * (1) measure of central tendency
      * what do scores “center” on
    * (2) measure of variability
      * how spread out are the scores

central tendency

• which to use
    * usually, we use the mean
      * but… problem of “outliers” - very unusual data point(s)

variability

• range
• standard deviation (SD)
    * average difference of scores from the mean
    * what if we just add up the deviation scores =0
    * solution = square the score
    * sum of all squared scores divided by sample size is called “variance”
    * standard deviation =square root of the variance

class notes 1/18/23

relative standing of a score

• often we want to express how a single score differs from the other scores
• 2ways
    * percentile ranked
    * the percentage of scores that fall below the score
      * 10th percentile =10% of score fall below that score
      * 95th percentile = 95% of scores fall below that score
• z-score
    * how far the score falls above or below the mean expressed in unit of SD
    * z-score = (score -mean) /SD

normal distribution

why normal distribution is important

• symmetrical
• how the area under the curve represents possibility of getting a particular score or higher
• when z is negative area beyond
• IQ score distrabution : mean=100 SD=15
• 85 or higher
    * what is the z score of 85
      * 85 has a z-score of 1
      * the difference -100 = awnser
• sampling error
    * the difference in samples not the same
• amount of sampling error depends on sample size
• standard error
• important for conducting statistical analyses (assessing probabilities )
• usually , if the probability is less than 5% of getting a score that extreame we say it is ststistically significant
    * alpha level
• this is an example of inferential statistics.

ch 3

• three claims, four validities
• interrogation tools for consumers of reasearch

variables

• variable - is something that varies between people and conditions.
    * at least two levels of values in a study
• depending on the study , some potential variables are heald constant
    * if so it is not considered a variable in that study

measured vs. manipulated variables

• measured → only documented
• manipulated → something the researcher varies at the start of a study
    * assign participants to different levels of a variable.
    * some cannot be manipulated at all
      * age/sex/ethnicity/height
    * some cannot be manipulated for ethical reasons
    * \
      * abuse vs. no abuse, poor va. healthy diet, schoolingvs. no schooling, social isolation
• \