repeated t

When do you use a repeated-samples t-test ⭐

when the same participants are measured before and after the IV

What is another name for repeated-samples t-test ⭐

paired samples t-test or within-Ss t-test

What type of design is repeated-samples t-test ⭐

within-Ss design

What is the null hypothesis for repeated-samples t-test ⭐

the mean difference between before and after scores is due to sampling error

What is the research question for repeated-samples t-test ⭐

whether the mean difference between before and after scores is due to sampling error

What is NOT being tested in repeated-samples t-test ⭐

not testing whether there is a correlation between before and after scores

What does the numerator represent in repeated-samples t ⭐

the difference between the two means (before and after)

How do you calculate degrees of freedom in repeated-samples t ⭐

N minus 1 where N is the number of pairs

What does N represent in repeated-samples t ⭐

number of pairs of scores (one before and one after per participant)

What effect size is used for repeated-samples t ⭐

Cohen’s d

How is Cohen’s d calculated in repeated-samples t ⭐

t divided by square root of N using the obtained t

What happens to the denominator when correlation between scores increases ⭐

denominator becomes smaller

What happens to t when denominator becomes smaller ⭐

t becomes larger

Why does higher correlation increase t ⭐

because subtracting a larger correlation term reduces the denominator

What is the advantage of repeated-samples t-test ⭐

smaller estimated SEdif makes it easier to reject H0

What is the disadvantage of repeated-samples t-test ⭐

repeated testing can create methodological problems

What is the key identifying phrase for repeated-samples t-test ⭐

same participants measured before and after

If participants are different across groups, should you use repeated-samples t-test ⭐

no, use independent samples instead

If before and after scores are not significantly correlated, how do you compute t ⭐

like independent samples t but df is still N minus 1

What is a matched pairs design ⭐

pairing different individuals with similar scores to act like a within-Ss design

Why does matched pairs justify repeated-samples t ⭐

because each participant has a comparable partner in the other condition

What are demand characteristics ⭐

when subjects realize what the study is looking for and this affects results

If you reject H0 in repeated-samples t, what do you conclude ⭐

there is probably a difference between before and after means

If you fail to reject H0 in repeated-samples t, what do you conclude ⭐

there is probably no difference between before and after means