Comparing Means One Flashcards
why do we compare means
usually to see if the means are different between two conditions
eg comparing mean RT for males with mean RT for females
what does statistically significant mean
unlikely to occur by chance
opposite is non-significant NOT insignificant
means if the experiment is repeated we’re likely to get the same results
describe student t-test
most widely used t test
3 types - independent samples. paired samples, one-sample
what does the t test test statistic (t-statistic) depend on
the size of the difference between the conditions
the standard error of mean in that difference`
what do we do when we have calculated t
we look up the associated p value in a degrees of freedom table
what do degrees of freedom depend upon
the number of participants
the different test method you’re using
what are other names for the independent samples t test
unpaired means t test
unrelated samples t test
between groups t test
what are the 4 things that must be true so we can use an independent sample t test
- data must be on a ratio or interval scale
- data must be normally distributed
- data in one group must be independent from data in the other
- data in the two groups must have similar variance
how do we choose which column to use to use in an independent samples t test
levenes test - if significance is more than 0.05 then variances are equal so use the EV row
if significance is less than 0.05 then variances arent equal so UEV row
