For the set of data below, find the line of best fit.
x -2 -1  0  1  2 
y  7  6  3  2  0 



  a. y = -1.8x + 3.6    
  b. y = -0.54x + 1.95    
  c. y = 3.6x - 1.8    
  d. y = 1.95x - 0.54    
  e. None of the others    

Do you have a TI-82 or higher?

Press STAT ENTER
Put the 5 x-values under L1
Put the 5 y-values under L2 

Press STAT then RIGHT ARROW to highlight CALC
Scroll down to LinReg(ax+b)
Press ENTER

Read

y=ax+b
a=-1.8
b=3.6
···

So substitute -1.8 for a and 3.6 for b in y = ax+b

y = -1.8x + 3.6

So it's choice 1.

Were you supposed to use a formula?

Edwin