KL Ch. 20 General Designs of Research

Question 1

Map of Experimental Group-Control Group: Randomized Participants

Answer 1

R ​X ​Y ​(experimental)

R ​-X ​Y​ (non-experimental)

Question 2

Experimental Group-Control Group: Randomized Participants controls for…

Answer 2

History, maturation, and presenting

Question 3

Advantages of Experimental Group-Control Group: Randomized Participant

Answer 3

1) Has the best built-in theoretical control system of any design, with one or two special exceptions.
2) It is flexible, theoretically able to extend to any # of groups with any # of variables.
3) If extended to more than on variable, it can test several hypothesis at one time.
4) It is statistically and structurally elegant.

Question 4

Map of Experimental Group- Group: Matched Participants

Answer 4

[Mr] ​ X​ Y ​(experimental)

[Mr] ​-X​ Y​ (control)

Question 5

Matching Versus Randomization

Answer 5

• Sometimes matching is done in the field, when the researcher wants to remain discrete.
• Can match when randomization would make the groups unequal.

Question 6

Matching by Equating Participants

Answer 6

o The most common method of matching is to equate participants on one or more variables to be controlled – called precision control method and matched by correlated criterion design.
o This method is able to detect small differences by ensuring that the participants in the various groups are equal on at least the paired variables.
o One requirement is that the variable which the individuals are matched, must be correlated significantly w/ the dependent variable. >.5 or .6

Question 7

Disadvantages of Matching by Equating Participants

Answer 7

• 1) Difficult to know which are the most important variable to match (Select those variables that have the lowest correlation with each other, but the most correlated with the DV)
• 2) The decrease in finding eligible matched participants as the # of variables used for matching increases.
• Matching effects generalizability – Researcher can only generalize results to other individuals having the same characteristic as the matched sample.

Question 8

The Frequency Distribution Matching Method

Answer 8

• Matches groups of participants in terms of overall distribution of the selected variable or variables.
• # of participants lost, not as great as individual-individual matching.
• The disadvantage is that combination of variables may be mismatched in various groups when there is more than on variable.