week2. 1-way ANOVA Flashcards
what are t-tests used for
to examine differences between two groups/conditions
what test are ANOVA’s an extension of
t-tests
are t-tests parametric or non parametric
parametric
what do 1-way ANOVA’s examine
the differences between 2 or more groups/conditions
what is a within-subject experiment
when all subjects do the same condition, repeated measures
what is a between-subjects experiment
when not all subjects do the same condition, independent groups
are ANOVA’s parametric or non parametric
parametric
that is it meant by type 1 error
when there is a false positive
what is parametric data
when the data comes from a “normal” sample and appears bell shaped on graphs, normal distribution
what is homogeneity variance
its when the average squared distance of score from the mean is the same across all groups sampled in the study
what does “factors” refer to in ANOVA’s
the independent variables, there must be at least 2 levels
what is the ANOVA conceptual basis
ANOVA’s are used to test whether the difference between means are statistically significant, they also compare the variation explained by the manipulation with variance left unexplained (e.g individual differences would be an unexplained reason there is a variation in scores between subjects)
how is the F value calculated
variance explained divided by the variance unexplained
why is it good that if our F value is a big number
it suggests there is more explained variance than unexplained variance
how does the F value effect the P value
the bigger the F value, the smaller the P value will be as there is less probability that the results consist of external factors interfering
what are the two df values that we have to report
the first df value (the smallest one that goes first in a report) stands for the number of factors - 1
the second df value (the larger one that we report after the first one) stands for the number of participants -1
what does df stand for and what does it mean
it stands for degrees of freedom and it represents the number of values that are free to vary in a a data set
what are the steps to carry out a 1-way between subjects ANOVA on SPSS
you need to make sure you DV and IV’s are in their separate columns, then you need go to analyse –> compare means –> 1-way ANOVA, then select you DV and IV’s
how do you report a 1-way ANOVA
F (df (number of IV’s -1), df(number of subjects -1) = F value, P= p value
why should Levenes test be non significant on the ANOVA summary table
if it was significant, it would suggest that there is high homogeneity variance, suggesting there may be external factors that have effected the data (needs to be below .005)
how do you carry out a 1-way within subjects ANOVA
make sure your DV and IV’s are in separate columns and then go to analyse –> general linear models –>repeated measures and then fill out dialogue boxes
what does Mauchly test of sphericity show
it is an extra assumption test, you want this to be non significant
what do you do if your Mauchly test is significant
you should consider doing a multivariate test
