The least-square regression line has a slope of:
m=(nΣxy-ΣyΣx)/(nΣx²-ΣxΣx)
and a y-intercept of:
b=(Σy-mΣx)/n
In this case: n=7, Σxy=4899, Σy=391, Σx=85, Σx²=1153 so
m=(7(4899)-391*85)/(7(1153)-85*85))=1058/846
b=(391*846-85*1058)/(7*846)=34408/846
So the line of best fit is:
y=(1058x+34408)/846 and if we approximated this as your answers see to have done....
y=1.25x+40.67
Ok so you would plug in 18 for the x so it would be 6(18)-12 and then 6x18 is 108 and 108-12=96 so your answer is 96
1/r = (3 1/2)/245
(3 1/2)r = 245
r = 245/3 1/2
r = 70
scale is 1 in to 70 miles.
Answer:
7.79 to the nearest hundredth
Step-by-step explanation: