Least Square Analysis (LSA): How to do it with
Cricket Graph
1.- Start Cricket Graph: a spread sheet will appear.
2.- Enter your x-values in Column 1 and the corresponding y-values
in Column 2.
3.- From the Graph menu, select New Graph ->
Scatter
4.- In the New Scatter Graph window, select Column 1 as the
Horizontal (X) Axis, and Column 2 as the Vertical (Y) Axis. Then
click
5.- From the Options menu, select Curve Fit...
6.- In the Curve Fit window, chose Linear from the
Method pull-down menu.
7.- Make sure that Display Equation is selected (black
rhomboid), and r is chosen in Coefficient Display
(r is the Correlation Coefficient, the closer to 1 the
better the fit of your data points to a straight line). Click
8.- A straight line will appear in your graph and an equation of
the form y=mx+b will be displayed, where m is
the slope of the line, and b the y-intercept.
9.- You can use these m and b values for your
calculations but remember, graphs should be handmade!
You can find Cricket Graph installed in the computers in
room 308 Havemeyer. This computers are there for you. You can also
use them for word processing. This room is supposed to be open
weekdays form 9am to 5pm. If the door is closed, ask someone in room
318 to open it for you.
This is what you have to do to start Cricket Graph in those
computers:
1.- From the Select a setup window, choose General
Chemistry Lab and click
2.- When prompted for a password enter 308.
3.- Click on the Cricket Graph III button. (If you are
prompted for another password, do not enter anything. Just click
)
4.- Remember to quit the program and the setup after you are done.
Enjoy!