1 way repeated measures ANOVA

Question 1

what are the characteristics of a study needed to perform a 1 way repeated measures ANOVA?

Answer 1

differences > continuous DV and categorical IV > within participants > paired t test > repeated measures ANOVA

Question 2

What values are reported in the SPSS write up?

Answer 2

F (effect df, error df) = [F value], p = [p value], np2 = [np2 value]

Question 3

what are the assumptions of a 1 way repeated measures ANOVA?

Answer 3

continuous DV, normal distribution, no outliers, equal sphericity

Question 4

what is equal sphericity?

Answer 4

there are no differences in the differences between conditions

Question 5

what should Mauchly’s test of sphericity show?

Answer 5

there should not be a significant outcome (above 0.05). if it is significant and equal sphericity is not assumed then read from the Greenhouse-Geisser row

Question 6

if the ANOVA is significant what do you do? what do you do if the ANOVA is not significant?

Answer 6

if significant run post hoc tests, if not significant don’t run post hoc tests

Question 7

how on SPSS do you get graphed data e.g. histograms?

Answer 7

ANALYSE > DESCRIPTIVE STATS > EXPLORE. put all in the dependent list. select dependents together (instead of factor levels together that is used for between ppts ANOVA)

Question 8

how on SPSS do you produce error bar graphs for within participant designs?

Answer 8

GRAPHS > LEGACY DIALOGS. select simple. select ‘summaries of separate variables’. move all DVs across to ‘error bars’

Question 9

A 1 way independent ANOVA tests the null hypothesis that all groups are the same. what is this referred to as?

Answer 9

an Omnibus Test

Question 10

give the steps of SPSS to run a 1 way repeated measures ANOVA

Answer 10

ANALYSE > GENERAL LINEAR MODEL > REPEATED MEASURES. type the factor name into ‘Within subject factor name’. type the number of levels in ‘number of levels box’ e.g. 3. select add. select define. select the 3 conditions and move them to ‘within subjects variables’. select plots. move the factor into horizontal axis

Question 11

what options should be selected on SPSS to run a repeated measures ANOVA?

Answer 11

descriptive stats, estimates of effect size

Question 12

how is the treatment effect/between conditions calculated?

Answer 12

in the same way as a between participants ANOVA by working out the difference between the grand mean and each condition mean

Question 13

what do between group differences include in a repeated measures ANOVA?

Answer 13

the effect (systematic variance) due to differences in treatment and the error (unsystematic) due to SAMPLING ERROR

Question 14

why do individual differences not need to be taken into account?

Answer 14

because we have the same people in each condition

Question 15

does only error due to sampling error (and not individual differences) give a greater chance of finding an effect?

Answer 15

yes as reduces the amount of error in the measurement

Question 16

within participant variance includes the error (unsystematic variance) due to ______ _____

Answer 16

sampling error

Question 17

effect (between conditions variance) / error (within participant variance) =

Answer 17

F ratio

Question 18

what does the F ratio do?

Answer 18

provide an indication of the effect with taking the error in the measurement into account

Question 19

if F is _____ than 1 then some of the variance is systematic (due to the treatment effect)

Answer 19

greater

Question 20

if F is _____ than 1 then none of variance is systematic (due to the treatment effect)

Answer 20

smaller