PSY 2812 Exam 2 Flashcards: Key Stats Terms & Definitions

what is signifcant findings in stats?

A P-value less than or equal to 0.05

degrees of freedom

The number of individual scores can vary without changing the sample mean

Sum of Squares (SS)

sum of squared deviations from the mean

variances

measures variability from the average or mean

What does One way Anova do?

tests the null hypothesis

omnibus test

tests for an overall effect, but does not provide info on which means are unequal

Is one-way ANOVA a omnibus test or not, and why?

yes, you can't tell the difference between what means are significant

What test do you have to do after the one-way ANOVA test to see WHICH means are significant?

post hoc test.

Assumptions for one way ANOVA test?

Normality, homogeneity of variance, independence of variances

normality assumption

The scores in each population are normally distributed

homogeneity of variance

This means that the population variances in each group are equal

independence of observations

each score in the group does not affect and is not affected by any other score in the group

One way Anova

A statistical test used to analyze data from an experimental design with one independent variable that has three or more groups (levels).

how is degrees of freedom written?

Statistically written as 'N-1' where N represents the number of subjects.

What do we do if the one-way ANOVA returns a statistically significant result?

we accept the alternative hypothesis (HA)

Why would we accept the alternative hypothesis (HA) in one-way ANOVA?

because at least two means from the group are statistically significantly different from each other

Which of the one way anova tests doesn't have a fix?

independence of observations

What if my one-way anova data fails the normality assumption?

change data so the shape of your distributions become normally distributed
run Kruskal-Wallis H Test

What if my one-way anova data fails the homogeneity of variance assumption?

run a Welch and Brown and /or Forsythe tests

If My p-value is greater than 0.05 (one-way anova), what do I do now?

not significant, no post hoc test

If My p-value is less than 0.05 (one-way anova), what do I do now?

signifcant, do the post hoc test

What do post-hoc tests do?

to confirm where the differences occurred between groups only when significant findings have happened

What do post-hoc tests attempt to control?

attempt to control the experiment-wise error rate (usually alpha = 0.05) in the same manner that the one-way ANOVA is used instead of multiple t-tests.

Is post-hoc a posteriori tests and why?

yes because it is after the study is done

Do you run multiple post-hoc tests for one-way anova?

no, just one

If your data met the assumption of homogeneity of variances, what post-hoc test do you use?

Tukey's post hoc test.

If your data did not meet the homogeneity of variances assumption, what post-hoc test do you use?

Games Howell post hoc test.