E-CodeRegression: linear, quadratic, exponential with r² — a TI-84 Plus CE program
REGRESS is a TI-BASIC program for the TI-84 Plus CE. Type X and Y lists: 2-variable statistics and correlation, then the linear, quadratic and exponential fits with r² (the exponential one also in Y terms, so the three are comparable).
What it asks for and what it shows
It asks for 2 values at its prompts. In the example below it shows N, XBAR, YBAR, SX, SY, CORR R, LA, LB, LIN R², QA, QB, QC, QUAD R², EA, EB, LN R², Y R².
Example run
One of its oracle test cases: “near-linear”. The inputs are typed in order, and the results are the values the case expects on the screen.
| Step | Value |
|---|---|
| You enter | |
| Input 1 | {1,2,3,4,5} |
| Input 2 | {2.1,3.9,6.2,7.8,10.1} |
| The screen shows | |
N= | 5 |
XBAR= | 3 |
YBAR= | 6.02 |
SX= | 1.58113883 |
SY= | 3.150714205 |
CORR R= | 0.9986517556 |
LA= | 1.99 |
LB= | 0.05 |
LIN R²= | 0.9973053289 |
QA= | 0.02142857143 |
QB= | 1.861428571 |
QC= | 0.2 |
QUAD R²= | 0.997467225 |
EA= | 1.662830828 |
EB= | 1.467315196 |
LN R²= | 0.9544027425 |
Y R²= | 0.9348456157 |
How it's checked
9 test cases, each checked against an independent method. Replayed key by key on a virtual TI-84 Plus CE, they make 133 checks.
How E-Code checks every program
Run it or put it on your calculator
- Open the library in the TI-84 Plus CE calculator and pick “Regression: linear, quadratic, exponential with r²” (REGRESS).
- Put it on your own calculator with a computer and a USB cable, or type it in by hand.
Related programs
- Hypothesis tests: z, t, two-sample t, chi-square
- Confidence intervals: z, t, proportion, two-sample
- Binomial, Poisson and normal probabilities
- One-way ANOVA
- Chi-square test of independence
All TI-84 Plus CE statistics programs · All TI-84 Plus CE programs