ANOVA test
In this exercise, we'll run the ANOVA test and analyze its outcome. Execute the code now and investigate the output.
Let’s examine the output: First, we have a numerical response variable (score on vocabulary test) and a categorical explanatory variable (class). Since class has four levels, comparing average scores across the levels of the class variable requires ANOVA.
Before we get to the ANOVA output we are presented with a series of summary statistics and the associated hypotheses.
Note that the alternative hypothesis is set to greater because F-tests are always onesided.
This exercise is part of the course
Data Analysis and Statistical Inference
Exercise instructions
Run the code and carefully read the exercise to examine the ANOVA output.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# The gss data frame is already loaded into the workspace
# The test:
inference(y = gss$wordsum, x = gss$class, est = "mean", method = "theoretical", type = "ht", alternative = "greater")