No, I just wanted them to make a graph with pencil on paper. Maybe I should’ve said “sketch” rather than “make” a graph to be more clear on this.

]]>The residual sd is just the residual sd. The errors aren’t normally distributed!

]]>1. From the exam problem: “We downloaded data with weight (in pounds) and age (in years) from a random sample of American adults.” You wouldn’t be downloading data on a random sample of 5 people!

2. We’d sketched many such scatterplots in class during the semester so the students had an idea of what they were supposed to do.

]]>> Make a graph of weight versus age (that is, weight in pounds on y-axis, age in years on x-axis). Label the axes appropriately, draw the fitted regression line, and make a scatterplot of a bunch of points consistent with the information given and with ages ranging roughly uniformly between 18 and 90.

Being a terrible sketcher (and that’s the understatement of the year…), I’d never been able to pass this one. Offering an alternative to propose a small code snippet to produce the required graph would have been a good way to spot who reminded tjhe salient points of the graph…

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