Ch. 9

Adding to your flow chart...



Within-subjects design: where every participant serves in every group/receives all levels of the IV.

reducing subject variability





















Advantages of Within-Subjects designs:

Source of variance df SS MS F, p
Between 1 72.9 72.9 3.99, .081
Within 8 146 18.25
Source of variance df SS MS F, p
Between 1 72.9 72.9 10.57, .031
Within 3 27.6 6.9






















Disadvantages











Possible Solutions

p1: easy medium hard

p2 medium hard easy

p3: hard easy medium

p4: easy hard medium

p5: hard medium easy

p6: medium easy hard

P1: a1 a2 a3 a4

p2: a3 a1 a4 a2

p3: a2 a4 a1 a3

p4: a4 a3 a2 a1

But...

Treatment x Order Interaction: when how you respond to treatments depends on the order of how treatments are presented

























Repeated Measures Designs

e.g., longitudinal



















Mixed designs









































Matched designs: matching subjects on a particular characteristic (one related to the DV)



Balance between reduction of error variance/risk of time-related effects:

eg., Does dress style affect shock reaction?

As a between groups design...





As a within-groups design...









As a matched design....