Identify the equation of the least squares regression line that most closely matches the data set.
a
b
c
d

To determine which of the equations match the data set given, we need to do a trial and error experiment. First, we will try the first equation:

 y = 0.17x + 13.2 

substitute x = 2, if the value of y is 65 then this is a possible equation.

Do the same for the rest of the data points and the equation which fits all the points is the answer 

Tan = opposite/hypotenuse
tan = 25/65
tan = 5/13