Question

Nikki recorded the number of learners who were absent from school each day due to illness. She did this for several days starting at the beginning of February. She then fit a linear function to model a set of data to predict y, the number of illnesses, from x, the number of days since the beginning of February.
The graph shows a plot of residuals for her function.

Which of the following about Nikki's linear function can be supported by the evidence shown?

Hint: If the points in a residual plot are randomly dispersed around the horizontal axis, a linear model is appropriate for the data.

A
A linear function is an appropriate model since there is a strong association between the two variables seen in the residual plot.

B
The curve-like pattern seen in the residual plot indicates that a linear function is not an appropriate model.

C
A linear function is not an appropriate model since some of the residuals in the residual plot are large.

Answer 1

The answer is B. The curve is too strong for a linear function to do anything but add a line to confuse.