ANOVA – Simple Introduction
SPSS One-Way ANOVA
SPSS One-Way ANOVA with Post Hoc Tests
SPSS Two Way ANOVA – Basics
Two-Way ANOVA with Interaction
How to Run Levene’s Test in SPSS?
How to Get (Partial) Eta Squared from SPSS?
Variance – What Is It?
Do you think running a two-way ANOVA with an interaction effect is challenging? Then this is the tutorial for you. We’ll run the analysis by following a simple flowchart and we’ll explain each step in simple language. After reading it, you’ll know what to do and you’ll understand why. We’ll use depression.sav throughout. The screenshot below shows it in variable […]
A car brand had 18 respondents rate 3 different car ads on attractiveness. The resulting data -part of which are shown above- are in adratings.sav. Some background variables were measured as well, including the respondent’s gender. The question we’ll try to answer is:are the 3 ads rated equally attractive and does gender play any role here?Since […]
What is Repeated Measures ANOVA? Repeated Measures ANOVA Assumptions Quick Data Check Running Repeated Measures ANOVA in SPSS Interpreting the Output Reporting Repeated Measures ANOVA 1. What is Repeated Measures ANOVA? SPSS repeated measures ANOVA tests if the means of 3 or more metric variables are all equal in some population. If this is true and we inspect a sample from our […]
Null Hypothesis Assumptions Example Repeated Measures ANOVA – Basic Formulas Post Hoc Tests Null Hypothesis The null hypothesis for a repeated measures ANOVA is that3(+) metric variables have identical means in some population. The variables are measured on the same subjects so we’re looking for within-subjects effects(differences among means). This basic idea is also referred to as dependent, […]
A hospital wants to know how a homeopathic medicine for depression performs in comparison to alternatives. They administered 4 treatments to 100 patients for 2 weeks and then measured their depression levels. The data, part of which are shown above, are in depression.sav. Data Inspection – Split Histogram Before running any statistical tests, let’s first just […]
SPSS One-Way ANOVA tests if the means on a metric variable for three or more populations are all equal. * The populations are identified in the sample by a categorical variable. For a very simple explanation of the basic idea, see ANOVA – What Is It?. SPSS One-Way ANOVA Example A farmer wants to know if the weight of parsley plants is […]
ANOVA -short for “analysis of variance”- is a statistical technique for testing if 3(+) population means are all equal. ANOVA – Null Hypothesis Test Statistic – F Assumptions for ANOVA Effect Size – (Partial) Eta Squared ANOVA – Post Hoc Tests The basic idea behind ANOVA: are 3(+) population means all equal? The two simplest […]
Research Question How to lose weight effectively? Do diets really work and what about exercise? In order to find out, 180 participants were assigned to one of 3 diets and one of 3 exercise levels. After two months, participants were asked how many kilos they had lost. These data -partly shown above- are in weightloss.sav. We’re […]
In ANOVA, we always report the F-value, degrees of freedom (df) and p for each effect -possibly just one for one-way ANOVA. P (“Sig.” in SPSS) tells us the likelihood of some effect being zero in our population. However, it doesn’t tell us how strong some effect is if it is not zero; we can’t conclude that p = 0.05 indicates a […]
Null Hypothesis Assumptions Levene’s test in SPSS Output Reporting Levene’s Test – What Is It? If we want to compare 3(+) groups on a metric variable, we usually want to know if they have different mean scores. In most cases, we’ll run an ANOVA in order to find out. However, this requires the homogeneity assumption which states that the population […]
The variance is a number that indicates how far a set of numbers lie apart.The variance is identical to the squared standard deviation and hence expresses “the same thing” (but more strongly). Variance – Example A study has 100 people perform a simple speed task during 80 trials. For each participant, 80 reaction times (in seconds) are […]
