# Checking model assumptions for a one-way ANOVA model with unequal sample sizes

Given an unbalanced completely randomized design with two treatment groups of unequal sizes and an appropriate one-way ANOVA parametric test, how can I properly check the validity of my model assumptions - namely, normally distributed errors, independence of the errors, homoscedasticity, and checking for outliers?

I started off checking for outliers by fitting a linear model to the data, and constructing a plot of the standardized residuals. To check for normality I inspected a normal probability plot, but I ran into trouble when checking for equal variances because I found that $s_{max}^2/s_{min}^2 > 3$. Then I realized that my two sample sizes were different - one is 90, and one is 95!

Hope my question isn't too basic. Thanks in advance.