Hit Stat key and select Edit option.
Clear each list by
arrowing up to L1 and hitting the Clear key and
the hitting the down arrow. Repeat for
all filled lists.
Enter the x-values for
your points into L1, and the y-values into L2. Make sure there are an equal number of items
in each list.
To graph the points, hit
the 2nd key followed by the Y= key. This gets you to Stat Plot.
Arrow down to 1:
and hit Enter key. The Plot
1 screen should now appear.
Highlight On by
placing the flashing cursor over On and then hitting Enter.
Move down to the Type:
option. Place the flashing cursor over
the 1st option of six (scatter plot, located upper left) and hit Enter.
Set the X-list to
L1 and Y-list to L2. The list options are 2nd
choices located above the numbers 1 6.
Select the type of Mark:
that you want to appear in your scatter plot graph. One of the first two is preferred.
Hit the Window
button along the top row and set max and min values to ones that are
appropriate for the data sets being used.
A square window will use an x:y ratio of 3:2. It may not be possible to use a square
window for every set of data.
Hit the Graph
button along the top row and your scatter plot graph should appear on the
screen.
Identifying the Best-Fit Line
Hit the Stat key.
The Stat menu should appear automatically.
Arrow over to Calc. The Calc menu should appear
automatically.
Look back at the scatter plot. What type of figure or graph would best represent the set of
points in the plot? Since the data
appears to be linear in this case, we want to use linear regression.
Reenter the Calc menu.
Hit the 4 key and LinReg (ax+b) should
appear automatically.
Hit the 2nd key and then the Stat
key. The List screen should appear
automatically. Hit the 1 key
and L1, should appear immediately after LinReg (ax+b).
Insert a comma following L1, the button
located just above 7.
Hit the 2nd key and then the Stat
key. The List screen should appear
automatically. Hit the 2 key
and L2, should appear on the 2nd row below LinReg
(ax+b) L1,.
Hit the Enter key and the pertinent information for
a linear equation will appear on the screen:
y=ax+b
a = slope
b = y-intercept
To check this answer, hit the Y= key. After clearing all previously entered
equations, highlight Y1=.
Hit the Vars key followed by the 5
key. Arrow over to the EQ
option and then hit the 1 key.
The calculated linear regression equation should now be automatically
entered after Y1=.