Student trouble with Notebook 4

young310jodi

I had two students today who had trouble in Section 3.2 (just above Section 3.3, see below); they confirmed they did not change any code. All other students had no issues. I'm not sure if it's easy to trouble-shoot on your end, but I thought I'd check with you before I went over their notebooks line by line.

After "We can now repeat this same process for all polynomial degrees." The code is run and they get this error:

"Error in eval(predvars, data, env): object 'default_rate' not found
Traceback:

predict…

dylarm

young310jodi I ran into this issue today as well with a student, in the exact same spot (code block for 3.2). What this means is that one of the models was constructed incorrectly, hence it not being able to find default_rate. For my situation, they had swapped the response and explanatory variable in sat_model_1. Instead of the correct

sat_model_1 <- lm(default_rate ~ SAT_avg, data = sample_dat)

they had written

sat_model_1 <- lm(SAT_avg ~ default_rate, data = sample_dat)

It's a mistake I've seen several times in the previous notebooks too, but it really bites them in NB4.

Let me know if that's the issue!

Edit to add: you can also figure out which line is causing the error by commenting out every line of code (adding a # to the start of the line) and then uncommenting the lines one by one.

young310jodi

That was the issue, thanks!