Answer:
The predicted grads for a student who studied for 105 minutes is 94.
Step-by-step explanation:
From the given figure the scatter points are (0,55), (0,65), (15,60), (15,65), (15,80),(30,55), (30,70), (30,80), (45,75), (45,80), (45,85), (60,80), (60,90), (60,95), (75,85), (75,90), (90,85), (90,95), (90,100), (120,80), (120, 95), (120,100).
The equation of best fit line is
[tex]y=ax+b[/tex] ... (1)
where, a is slope and b is initial value.
[tex]a=\frac{\sum_{i=1}^nx_iy_i-n\overline{x}\overline{y}}{\sum_{i=1}^nx_i^2-n\overline{x}^2}[/tex]
[tex]b=\overline{y}-b\overline{x}[/tex]
Using graphing calculator we get,
[tex]a\approx 0.2835[/tex]
[tex]b\approx 64.3775[/tex]
Substitute the value of a and b in equation (1).
[tex]y=0.2835x+64.3775[/tex]
Substitute x=105 in the above equation to find the predicted grads for a student who studied for 105 minutes.
[tex]y=0.2835(105)+64.3775[/tex]
[tex]y=94.145[/tex]
[tex]y\approx 94[/tex]
Therefore the predicted grads for a student who studied for 105 minutes is 94.
