Chapter 6 Flashcards
Between-Subject Design
A subject receives either level A or level B of the Independent Variable rather than both.
Advantages of a between-S design:
-Subjects are naive about the procedures
-There won’t be practice effects that could confound the study
Disadvantages of a between-S design:
-We need more subjects than a within-s design.
-Differences between conditions could be due to the IV but they could also be due to individual differences.
Equivalent groups
Groups are equal to one another in every way except for the IV.
To accomplish equivalent groups, we can use:
1-Random Assignment
2-Matching
Blocked Random Assignment
is a procedure that ensures that every condition has a S randomly assigned to it before it is repeated a second time. Each block contains all conditions in a randomized order.
Matching
Subjects are first paired on some characteristic that could be expected to affect the DV. Then one member of each pair is randomly assigned to the conditions being tested.
Within-Subject Design
It is also known as the repeated measures design. In this design, S receives both A and B levels of the IV.
Advantages of Within-S Design
-fewer subjects are required
-eliminates the equivalents groups problem
-there are no longer individual differences between groups hence it’s the same group being retested.
Disadvantages of Within-S Design
Order effects
Order Effects
When a S finishes one trial/condition, it could affect the subsequent trials.
Two Types of Order Effects
1-Practice Effects (performance improves over trials)
2-Fatigue Effects (performance deteriorates over trials)
How to control for Order Effects
use counterbalancing, which is when we use more than order.
Types of Counterbalancing Techniques:
-Complete Counterbalancing
-Partial Counterbalancing
-Balanced Latin Square Design
Complete Counterbalancing
Where every possible order is used at least once.
Partial Counterbalancing
You randomly pick and use a subset of all possible orders.
Balanced Latin Square Design
Allows you to get away with relatively few different orders because things are “balanced”. It ensures that every condition occurs equally often in every sequential position. It also ensures that every condition precedes and follows every other condition exactly once.
-The # of Ss must be equal to or a multiple of the # of rows in the square.
Reverse Counterbalancing
The conditions are presented in one order and then in the reverse order as many times as necessary.
