Chapter 12: Statistics 278
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.
18. Press y , 2 to select 2:Plot2 from the
STATPLOTS menu. The stat plot editor is
displayed for plot 2.
19. 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 † ãRä
ãEä ãSä ãIä ãDä (alpha-lock is on) to specify
Ylist:RESID for plot 2. Press † Í to select ›
as the mark for each data point on the scatter plot.
20. 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.
21. 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.