Problem:
Given the following table:

 Year: DJ Average 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 824 972 882 1027 1252 1198 1537 1927 2015 2144
[Extracted from the Chance site.]

find and graph the least squares regression line.

Visualization:
Using Maple:

First, we'll plot the data points:

> with(plots):
> plot([[80,824], [81,972], [82,882], [83,1027], [84,1252], [85,1198], [86,1537], [87,1927], [88,2015], [89,2144]], style=point, symbol=diamond, color=blue);

We'll store this information using the name dataplot:

> dataplot:=":

We'll now use the Maple command fit:

> with(stats):
> fit[leastsquare[[x,y], y=a*x+b, {a,b}]]([[80, 81, 82, 83, 84, 85, 86, 87, 88, 89], [824, 972, 882, 1027, 1252, 1198, 1537, 1927, 2015, 2144]]);

We now plot the graph of the least squares line:

> plot(25882/165*x-1959692/165, x=80..89);

We'll store this information using the name lineplot:

> lineplot:=":

Finally, we combine these plots:

> plots[display]({dataplot, lineplot},view=[79..90, 800..2150]);