For 25 Year 8 students, daily reading time (minutes, 9 to 40) and a reading test score were recorded. One student read 35 minutes a day but scored very low because they were sick on test day.
With all 25 students: y^=12.4+0.85x, r=0.62. Without that student: y^=8.1+1.12x, r=0.88.
Figure 1 shows the data with both fitted lines; the student who was sick on test day is shown in red.
Scatterplot of reading test score against daily reading time (9 to 40 minutes) for 25 students, with one student who was sick on test day shown in red at 35 minutes with a very low score; the fitted lines with and without that student are drawn. Data are illustrative.Facts you may need
(a)
Use Figure 1 to describe the effect of the unusual student on the model.
(b)
Predict the score for a student reading 20 minutes a day using each model.
(c)
Which model should be used? Justify.
Daily reading time and reading scores — Scholarship Statistics | Xametric
