11- Repeated-Measures Design Flashcards
what is the main advantage of repeated-measures design?
the main advantage is that it uses exactly the same individual in all treatment conditions- no risk that participants in 2 separate groups have differences (age, sex, etc)
Repeated-Measures Design: (within- subject):
the dependent variable is measured TWO OR MORE TIMES for each individual in a SINGLE SAMPLE
matched-subject:
each individual in one sample is matched with an individual in the other sample
what is the major difference with a t statistic in repeated-measures, as opposed to other t statistics?
the major distinction is it is based on DIFFERENCE OF SCORES, rather than raw scores
mean difference (MD)
foruma is: ∑D/ n
what is the null hypothesis stating for a repeated-measures design?
the mean difference for the general population is ZERO.
what is the alternative hypothesis stating for a repeated-measures design?
the mean difference for the general population is NOT ZERO.
difference scores are identified by….
the letter D, rather than X
for step 2) of a hypothesis test, you must calculate….
-degrees of freedom,
-critical t value
-mean difference (MD)
-and sum of squares difference (SSD)
what is an advantage repeated-measures deign has over independent measure design?
repeated-measures deign typically REQUIRES FEWER SUBJECTS than an independent- measures design
repeated-measures design is well suited for __________, _________, or _________.
repeated-measures design is well suited for STUDYING LEARNING, DEVELOPMENT, or other CHANGES taking place OVER TIME.
what is the PRIMARY ADVANTAGE of repeated-measures?
it reduces or eliminates problems caused by individual differences (age, IQ, gender) which can influence and affect results
what is the PRIMARY DISADVANTAGE of repeated-measures?
time related factors and order effects: factors that cause a score to change from one treatment to the next, often measured at 2 different times
how to deal with the DISADVANTAGE?
COUNTER BALANCE: distribute any outside effects evenly over the 2 treatments- SPLIT INTO 2 GROUPS (group a: treatment 1-2) (group b: treatment 2-1)
