Quiz 3 - Research Strategies & Designs

what are the three advantages of within-subjects design?

• 1. it avoids the problem of person-to-person variability

• 2. it controls for extraneous variables

• 3. it requires fewer participants than a between-subjects design to have the same amount of power

what are the three disadvantages of a within-subjects design?

• order effect:

  • an effect from order of treatments

• carry over effect

  • an effect from a previous trial or condition and not from the current trial

  • solution: counterbalancing (alternate order)

List the different types of research strategies. Briefly go over the differences between each.

• Descriptive

  • measures variables as they exist naturally

  • ex.

    • what is the typical number of text messages received/day?

    • what is the average number of hours slept/day?

    • what percentage of students voted in the presidential election?

• Correlational

  • a measure of the relationship between variables

  • it examines the strength and direction of a relationship

  • ex.

    • is there a relationship between sunlight and depression?

    • is there an association between exercise and depression?

    • is there a link between genetics and depression?

• Experimental

  • tests for cause-and-effect relationship by randomly assigning participants to conditions, and manipulating one variable (the IV) while measuring a second variable (the DV)

  • ex.

    • testing the effect of exercise vs no excercise on cholesterol

    • testing the effect of studying with music vs studying without music on test performance

    • testing the effect of caffeine vs no caffeine on hr

• Quasi-Experimental

  • tests for a cause and effect relationship and limits threats to internal validity but lacks random assignment

  • ex

    • blah

    • blah

• Nonexperimental

  • determine if a relationship exists between variables by comparing different groups of scores. it doesn’t attempt to minimize threats to internal validity or to explain the relationship

  • ex.

    • is there a difference in verbal skills between men and women?

    • is there a difference in math skills between left- and right-handers

    • is there a difference in long-term memory between cats and dogs?

a

b