Comparing two means Flashcards
What does a t test statistic tell us?
if the difference between the means of two groups is different from zero.
what does an Independent t test do?
compare two means that come from conditions consisting of difference participants.
What does a paired samples t-test (dependent t-test) do?
compares two means that come from conditions consisting of the same or related participants.
sampling theory: on average sample means are similar to….
the population mean.
sampling theory: on average most samples should have…
similiar means which means the difference between the means is zero.
sampling theory: occasionally…
one or both samples will have means very deviant from the population mean.
the standard deviation of the means from many samples of the same populaiton is called
the standard error of differences.
the means of many samples from the same population will be…
normally distributed.
a small standard error of difference suggests
difference between means will be close to the population mean.
three steps for performing a t-test
explore data, run the t-test, calculate an effect size (bayes factor)
t-test: explore data
check for outliers, normality, homogeneity by doing boxplots, histograms, descriptive statistics.
run the t-test
bootstrap if problems with the data
what does a t-test bayes factor do?
quantifies the ratio of how probable the data are under the alternative hypothesis compared to the null.
