Texas Instruments TI-73 EXPLORER - Manual (Page 144)

138
Chapter 7: Statistical Analyses
7307ENG.DOC CH 7, Statistical Analyses, English Julie Hewlett Revised: 07/29/98 12:07 PM Printed: 05/19/99
9:00 AM Page 138 of 22
Manual-Fit Manual-Fit - v ! 3 3
Manual-Fit
allows you to fit a line to plotted data on the Graph
screen manually (as opposed to the calculator automatically
drawing it for you). You can execute
Manual-Fit
from either the
Graph screen or the Home screen.
From the Graph screen, select
Manual-Fit,
and then draw the
line (steps provided below). The linear equation in the form
y=ax+b
is shown at the top of the Graph screen. You can use
the cursors to adjust the line, if necessary, and the
a
and
b
equation values change accordingly.
From the Home screen,
Manual-Fit
accepts one optional
argument, Yn. The calculator stores to Yn (in the Y= editor)
the
ax+b
equation that manually fits the plotted data. To access
the
Y
n
variables, press - }
2
.
Manual-Fit
Yn
From either the Home screen or the Graph screen or Program
editor, select
Manual-Fit
after you have plotted the stat plot. To
draw the
Manual-Fit
line:
1. Position the cursor at the beginning of the line segment
that you want to draw, and then press b.
2. As you press the cursor keys, the line is drawn and the
slope is adjusted. When you have matched the plotted
points as desired, press b.
3. The line segment is drawn across the entire screen and
the
ax+b
equation is shown at the top of the Graph screen.
4. Continue to adjust the line’s slope with $ and #, and the
y-intercept with ! and ", if desired.
5. If you specified a
Y
n
variable on the Home screen, you can
view the selected and defined equation in the Y= editor
(&). If you no longer want to view the Manual-Fit line,
deselect it in the Y= editor by highlighting the
=
and
pressing b.