Chapter 11- One Way ANOVA Flashcards
When will the F- distribution approach normal distribution?
The F distribution will approach normal distribution when there are large samples sizes
What other distribution is like the F-distribution?
The F distribution is like the T when there are only 2 samples
What is the F-statistic?
The F-Statistic is a ratio of two measures of variability
What are the two measures of variability with the F statistic?
Between-groups and within-groups
What is between-groups variance?
Between groups is the estimate of the population variance based on the spread between group means
What is within-groups variance?
Within groups variance estimate of the population variance based on the average variability within each group
How is the F-statistic calculated?
The F-statistic is calculated by dividing the between groups variance by the within groups variance
How do you increase the F-statistic?
The F statistic can be increased by increasing the variability between means or decreasing the variability within groups
What is a one-way ANOVA?
One nominal independent variable with more than 2 levels, scale dependent variable
What is a One Way Within Groups ANOVA?
One Way Within Groups ANOVA is more than 2 samples, composed of the same participants. Also called repeated measures
What is a One Way Within Groups ANOVA?
One Way Between Groups ANOVA is more than 2 samples, each composed of different people.
What are the assumptions of an ANOVA?
Random and independent, population distribution of dependent variable is normally distributed, and samples come from populations with same variance (homoscedasticity)
What is heteroscedasticity?
Heteroscedasticity is when samples come from different variances
What are the 6 steps of ANOVA Hypothesis Testing?
- Identify pops, distributions, and ck assumptions
- State null and research/alternative hypothesis
- Determine characteristics of null distribution
- Determine Critical Values
- Calculate test statistic
- Make a decision
How do you calculate the dfbetween?
Calculate the number of groups-1
How do you calculate the dfwithin?
Calculate the total number of participants - the number of groups
How do you calculate the dftotal?
Calculate the total participants-1
What is the MS and how do you get this number?
Mean Square. It is the SS divided by the degrees of freedom
What is the SS?
The SS is the sum of squares; its the sum of deviation scores squared
What is the SS total?
The SS total is the sum of all squares ignoring the separate groups
How do you calculate the MS between?
The MS between is calculated by dividing the SS between by the dfbetween
How do you calculate the MS within?
The MS within is calculated by dividing the SSwithin by the dfwithin
How do you calculate the F statistic after calculating the MS between and the MS within?
The F statistic is calculated by dividing the MS between by the MSwithin
What formula is used to calculate effect for ANOVAs?
R2
What is the R2 and what are the sizes?
R2 is the proportion of variance in the dependent variable that is accounted for by the independent variable. You can convert this amount to a percentage. The sizes are sm= .01, med=.06, and large is .014
What happens when multiple comparisons are made?
The more comparisions we do, the more likely we mare going to make a type 1 error
What is a post hoc test?
A post hoc test is a test used to compare multiple groups (two at a time)
What does the post hoc test protect from?
A post hoc test protects from inflating a type 1 error
When is a post hoc test conducted?
A post hoc test is only conducted if the overall F test is signifigant
What is the name of the most common post hoc test?
Tukey HSD
What is the critical value of the Tukey HSD?
Q-value +/- 3.77
