two tasks in homework 4 seem to be identical

[rjoberon]

In homework 4 task 2:

To see what the relationship between income and education looks like, group the dataset by educ and plot mean income at each education level.

is IMHO identical to task 5:

Use groupby to group respondents by educ, then plot mean realinc for each education level.

It could be more appropriate to group by sex instead (this would fit to the preceding analysis).

[AllenDowney]

That is actually as intended -- plotting the data this way is the background we'll compare with the predictions from the model. It's the same background for the two models.

I see why that's confusing though -- I will revise that if I have a chance.