Today we learn how to obtain useful diagnostic information about a regression model and then how to draw residuals on a plot.

The key concept of factor analysis is that multiple observed variables have similar patterns of responses because of their association with an underlying latent variable, the factor, which cannot easily be measured. For example, people may respond similarly to questions about income, education, and occupation, which are all associated with the latent variable socioeconomic status.

OK. Indeed, R has a longer learning curve than other systems, but don’t let that put you off! Once you master the syntax, you have control of an immensely powerful statistical tool. Actually, much of the syntax is not all that difficult. Don’t believe me? To prove it, let’s look at some syntax for providing summary statistics on a continuous variable.

How to do it In stratified sampling, the population is divided into different sub-groups or strata, and then the subjects are randomly selected from each of the strata. So, in the above example, you would divide the population into different linguistic sub-groups (one of which is Yiddish speakers). Here are two simple steps you should follow: