TI-83 Plus

Correlation and Regression

Data: Spiegel’s Probability and Statistics (Schaum’s Outline series) problem 8.11

First row: x = father’s height (inches)

Second row: y = son’s height (inches)

65	63	67	64	68	62	70	66	68	67	69	71
68	66	68	65	69	66	68	65	71	67	68	70

TI-83 Plus Correlation

Make sure DiagnosticOn is set. To set it,

2^nd [CATALOG] i.e., 2^nd 0

Select DiagnosticOn Scroll to it and press ENTER.

ENTER

Now the correlation r and coefficient of determination r² will be calculated when you do regression.

TI-83 Plus Least-Squares Regression

Enter the father’s heights into list L1. (Use STAT 1:Edit.)

Enter the son’s heights into list L2.

STAT

CALC

8 :LinReg(a + bx)

2^nd [L1]

2^nd [L2]

ENTER

Scatterplot with Regression Line

Before hitting ENTER in the above sequence, do these steps:

VARS

Y-VARS

ENTER 1:Function

ENTER 1:Y1 This will make the regression equation Y1 = a + bX.

and then press ENTER.

Plotting the scatterplot and regression line

Use 2^nd [STAT PLOT] to turn on only Plot1, say, select the scatterplot, and make the Xlist L1 and the Ylist L2.

WINDOW Make sure that the Xmin, Xmax, Ymin, and Ymax values show your scatterplot data.

GRAPH will show your scatterplot with the regression line drawn in.

Residual plot

After the TI-83 Plus has calculated the regression line, the residuals are stored in the LIST screen.

To get a residual plot, then, do the following.

2^nd [LIST] 2^nd STAT

7 :RESID

STO

2^nd [L3] Store the residuals in L3 or other free list.

Do not destroy your Xlist.

ENTER

2^nd [STAT PLOT]

Select Plot1 (or your previous plot) and change Ylist to L3.

Deselect your regression line Y1.

STAT

1 :Edit

Scroll down list L3 to determine bounds on your residuals. (Or use 1-Var Stats on L3 to find the min and max.)

WINDOW

Set Ymin and Ymax to include your residuals.

GRAPH