Question

Which of the following is a suitable equation for a line of best fit for the data set below?

Time Spent Studying (minutes)
0
30
30
30
60
60
90
90
120
120
120
120
180
180
Grade on Test (%)
28
54
45
39
63
53
75
85
78
92
100
98
89
99
95

A. Y=30/11 x- 1,842/11
B.y=11/30 x+111
C. y=30/11x + 3,558/11
D. y=11/30x+ 45

Answer 1

Answer: D: y = (11/30)x + 45

[Note: The list is missing a data point. I did what I could]

Explanation:

See data plot.

The equation states that a minium expected grade with no study time is 45 percent. Every mionute studied after that adds (11/30) percent to the grade. E.g., 90 minutes of study:

(11/30)*(90) = 33

Add to 45 to get a predicted score of (33 + 45) = 78