Step-by-step explanation:
Mean of the number of new stores = (14 + 27 + 48 + 80 + 110 + 153 + 261 + 403 + 681)/9
Mean = 197.4444
Mx = 197.4444
Mean of the year = (1986 + 1987 + 1988 + 1989 + 1990 + 1991 + 1992 + 1993 + 1994)/9
Mean = 1990
My = 1990
Regression line:



Plotting the line of best fit: