拉丁方以表格的形式被概念化,其中行和列代表两个外部变量中的区组,然后将自变量的级别分配到表中各单元中。简单的说就是某一变量在其所处的任意行或任意列中,只出现一次。
2 Experimental Methods
•It is important to select the right experimental method so that the results of the experiment can be generalized
•There are mainly two experimental methods
•between-groups:
each subject is assigned to one experimental condition
- Each subject performs under all the different conditions
- Repeated-measure
•within-groups:
each subject performs under all
the different conditions
- Each subject is assigned to one experimental condition
Within-subjects | Between-subjects | |
Learning effect | Avoids interference effects (e.g. practice / learning effect) |
|
Longer time for each participant (larger impact of fatigue and frustration) |
Shorter time for each participant (less fatigue and frustration) |
|
Individual difference can be isolated | Impact of individuals difference | |
Easier to detect difference between conditions |
Harder to detect difference between conditions |
|
Requires smaller sample size | Require larger sample size | |
Counterbalance/randomize the order of presenting conditions |
Randomized assignment to conditions or matched groups | |