Operation Manual

Chapter 12: Statistics 187
Notice that the first three residuals are negative. They correspond to the shortest pendulum string
lengths in L1. The next five residuals are positive, and three of the last four are negative. The latter
correspond to the longer string lengths in L1. Plotting the residuals will show this pattern more clearly.
Notice the pattern of the residuals: a group of negative residuals, then a group of positive residuals,
and then another group of negative residuals.
19. Press y ,
2 to select 2: Plot2 from the
STAT PLOTS menu. The stat plot editor is displayed for
Plot 2.
20. Press Í to select
On, which turns on Plot 2.
Press † Í to select " (scatter plot). Press †yd
to specify
Xlist:L1 for Plot 2. Press y7to lock the
alpha key. Press † ã
Rä ãEä ãSä ãIä ãDä to specify Ylist:RESID
for Plot 2. Press † Í to select › as the mark for each
data point on the scatter plot. Press † to select a color
(the default color for Plot 2 is RED).
21. Press o to display the Y= editor.
Press | to move the cursor onto the
= sign, and then
press Í to deselect Y1. Press }Í to turn off
Plot 1.
22. Press q
9 to select 9:ZoomStat from the ZOOM
menu. The window variables are adjusted automatically,
and Plot 2 is displayed. This is a scatter plot of the
residuals.