Follow the instructions in the "Statistics" chapter of the Guidebook. If you don't have your Guidebook handy, you can download it from the manufacturer's web site at http://education.ti.com
The drawing of the scatter plot proper is explained in the last part (Part F). You might want to jump right to it.
Before
doing statistics, you have to prepare the calculator by clearing old
data that may generate errors.
A. TO CLEAR OLD DATA
B. RUN the
SETUP EDITOR Command
C. TURN DIAGNOSTICSON option
(optional)
To
obtain the correlation coefficient in a statistical analysis on the
TI8xPlus family of calculators you must activate the DIAGNOSTICSON
option. To access the command
From now on, if a
correlation coefficient has meaning for a regression model, it will be
calculated along with the other statistical results. If it has no
meaning to the model it will not be calculated.
D. ENTER
THE DATA
Press [STAT][1:Edit]
Type in your D (X ) values
in L1
and the N (Y) values in L2 (see picture 1). Sorry the picture does not
have YOUR values.
TO
OBTAIN statistical RESULTS (optional)
Here is
what you get (THESE~ARE NOT YOUR RESULTS). Your results will be
different.
Notice
the Down Arrow next to n=7. That means the results screen has more
values. Press the Down Arrow
You
notice
that the n=7 line now has an arrow pointing Up. Notice the Down
Arrow on the bottom line (more data is coHow do I create a scatter plot? - 37fb2ba.jpg is the rest of the
statistical results.
There
is no arrow at the bottom of the picture. End of statistical results.
The
screen
captures with 2-Var Stats summarize all the statistics.
However
there is no correlation coefficient, no line of best fit, etc. To
obtain that you have To perform a regression analysis.
E.
PERFORM A REGRESSION ANALYSIS
To
perform a regression analysis, you must try several regression models
and then find the one that mimicks the raw data best. Select Regression model (Exeample Esponential, linear, sine, quadratic, etc.) Here I selected Exponential
Here
are your results. (These are your actual results)
You
also have r and its square.
Since the
equation is saved in the Y1 function it can be superposed on the scatter plot. You just have to press
GRAPH and it will be drawn. But that will not tell how good the fit is,
until you see the function drawn on top of the raw data.
F. DRAWING
THE SCATTER PLOT AND BEST FIT CURVE ON SAME SCREEN
Regardless
of the curve of best fit, you can draw a scatter plot as follows.
Here
is the configuration screen
Here
plot1
is active (ON), it is scatter plot (first icon) the XLIST is L1
by default but you can change it to some other list. Notice the
highlighted A cursor on XLIST line. It means that the [ALPHA] keyboard
is active.
On the line Mark you can choose the appearance of the raw
data point.
And hereHow do I create a scatter plot? - d6e8e98.jpgwo graphs: the raw data scatter
plot and the line of best fit on the same screen. On the picture the
ZoomStat option was used.
Now,
it is up to you to accept this model or to try another model.
Comments:
Apr 19, 2010 - I tried to
edit the post to address your particular need but after several crashes
I decided to paste it as is.
The particular parts that are of
concern to you are Part E (performing a regression analysis) and the
following one where the best fit and the dcatter plot are
superposed on the same display.
As you have guessed you must
select QuadReg.
SOURCE: When I try to graph a scatter plot from 2 lists, I
Hello,
Press [2nd][STAPLOTS][4:StatPlots Off] [ENTER][ENTER].
Press [STAT][5:SetUp Editor] [ENTER]ENTER]
Configure the statpolt as in the picture (for a scatter plot)
Restart you statistical graphing.
If that does not solve the problem, reset the RAM
Press [2nd][MEM][7:Reset][1:All Ram][2:Reset][ENTER], then [CLEAR] the message on screen.
Hope it helps.
SOURCE: steps from manual on how to do stemp plot box
To make a plot, first you will need to define a list. To do this, press "{", then enter the values of your list, separating each value with a comma, and ending the list with "}" then store (STO>) the list into a list variable ("2nd" + "1", "2", etc.). For a box plot, you will need only one list, and for a scatter plot, you will need two. One for the independent variable, and one for the response variable; that is, one for the X and Y axis, respectively. To make your plot, open the plot menu ("2nd" + "Y=") and select a plot. From there, you may select the type of plot and which lists to use as values.
To find the residuals for the line of best fit, from the home screen, press "STAT", then move one right to "CALC", then select option 4, "LinReg(ax+b)". Once this command is on your home screen, follow it with your X and Y axis lists, separated by a comma, eg: "LinReg(ax+b) L1, L2". Press enter. In a moment, you will be provided with 'a' and 'b' values. Plug those residuals into your "Y=" menu in the form "ax+b", replacing 'a' and 'b' with the residuals, and the line of best fit will be drawn across your graph.
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