Since 2 5.30 we reject the null hypothesis of equal means in all groups. Variances are 30.03, 11.97, and 19.62. These plots illustrate the clustering of the observations in each group about the group means. Since the sample sizes are a bit unequal, if one wanted to be very careful, the best analysis here would be to use something like BMDP7D which we illustrated with the IBS data to use a one-way anova method that did not require the equal variance assumption. The regression line passes through the sample means.
Correlation is the square root of the R-squared value expressed in decimal form.
An alternative to transformations is to fit a polynomial. Unusual Observations Obs. days size Fit Stdev. Fit Residual St. Notice the t statistic for the coefficient of the quadratic term in this model. It is highly significant, indicating a substantial quadratic component to these data.