research psych 3

  1. (Quasi experimental) variance is necessary...
    in any research
  2. (Quasi experiental) 2 forms of variance
    -systematic between groups variance

    -nonsystematic within groups variance
  3. (Quasi experiental) Systematic between groups variance
    • -experiemnetal variance (due to IV)
    • *differences will be because of IV

    • -extraneous variance (due to confounding variable)
    • *differences will be other factors involved
  4. (Quasi experiental) Controlling variance (3)
    • -maximizing experimental variance
    • *make sure there are real differnces between groups

    • -controlling extraneuous variables
    • *groups are similar a start of experiment

    • -minimizing error variance
    • *control with careful measurement or with specific designs
  5. (Quasi experiental) < designs
    -do not include the critical controls of experimental designs

    -may still be used but caution
  6. (Quasi experiental) 4 designs of quasi exp.
    -single-group, posttest only design

    -single group, pretest and pottest design

    -pretest and posttest, natural control group design

    -ex post fact design
  7. (Quasi experiental) Ex post facto design
    -a very weak design

    -not good science

    -does not control confounding variables

    *what we do when we try to figure out, after the fact, what caused somehting to happen

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    N.O people >    Hurricane      > how depressed were they? they were already depressed before the hurrican
  8. (Quasi experiental) Single group posttest only
    -no control over confounding variables

    -weak design, stronger than de facto

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    *we tend to use an implciti control group (what we think would have happened if there had been no manipulation)
  9. (Quasi experiental) Single group pretest and postest design
    • -pretest documetns change but factors other than the treatment cold have accounted for the change
    • *history, maturation, regression to the mean etc.

    • ex) people may have adjusted to their stress
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  10. (Quasi experiental) Pretest and postest, natural control group design
    -like an experiment except that participants aer not randomly assigned to groups

    • -it does not control selection but has a strong design
    • *selection can play a major role in certai experiments
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  11. (experimental design) characterteristics of exp. design
    -more than 2 levels of the IV

    -random assingment

    -controls threat to validity
  12. (experimental design) Randomized pretest only control group designs
    -random assignment controls selection

    -other confoudning variables are controlled by comparing the treatment and no treatment group

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    • *strong common design
  13. (experimental design) randomized, pretest-postest, control group design
    • -adding pretest allows us to quantify the amount of change following treatment
    • *allows us to verify groups were equal at start of experiment

    • -strong basic research design with excellent control over confounding variables
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  14. (experimental design) multilevel, randomized, between subjects design
    • -may or may not include a pretest
    • *posttest is necessary

    -multigroup extension of the basic experimental design

    • -controls virtually all sources of confounding variables
    • *we can have as many groups possible
    • **most common used in drug companies
    • ***how much dosage works best
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  15. (experimental design) Solomon 4 group design
    • -combines 2 basic experimental designs
    • *randomized postest only, control group
    • *randomized, pretest-postest, control group design

    -allows the assesment of an interaction between the pretest and the treatment

    *uncommon research design

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  16. Research is design to...
    measure and control sources of vriance
  17. experienteal design have 2 elements
    -random assingments of participants to conditions

    -at least one control group
Card Set
research psych 3
single variable indepdendetn variable groups designs