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How to show r and r² on a regression on a TI-83 Plus

By E-Code · updated

Press 2nd CATALOG (above 0), x⁻¹ to jump to D, ▼ to DiagnosticOn and ENTER twice. Now STAT ▶ CALC 4 (LinReg(ax+b)) and ENTER shows r and r² under a and b.

Before you start

Type 1, 2, 3, 4, 5 into L1 and 2, 4, 5, 4, 5 into L2 first (STAT, ENTER), then 2nd QUIT.

STAT ENTER 1 ENTER 2 ENTER 3 ENTER 4 ENTER 5 ENTER ▶ 2 ENTER 4 ENTER 5 ENTER 4 ENTER 5 ENTER 2nd MODE

Step by step

  1. Open CATALOG. 2nd 0 Press 2nd, then 0. CATALOG lists every command A to Z. Your data is already in L1 and L2.
  2. Jump to D. X⁻¹ Letters are on, so press x⁻¹ (the D key): the list jumps to the commands starting with D.
  3. Down to DiagnosticOn. ▼ ▼ ▼ ▼ ▼ ▼ ▼ Press ▼ until the arrow points at DiagnosticOn.
  4. Paste it. ENTER Press ENTER. DiagnosticOn is pasted on the home screen.
  5. Run it. ENTER Press ENTER. Done: regressions will now also show r and r².
  6. Open STAT. STAT Press STAT.
  7. The CALC tab. ▶ Press ▶ to CALC. Item 4 is LinReg(ax+b), the straight line of best fit.
  8. Pick LinReg(ax+b). 4 Press 4. It's pasted on the home screen.
  9. Calculate. ENTER Press ENTER. With no lists after it, LinReg uses L1 for X and L2 for Y.
  10. Read r and r². a = .6 and b = 2.2 give y = .6x + 2.2. r = .77 says the points rise fairly closely along the line; r² = .6 means the line explains 60% of the spread.

What the screen shows

a = .6 and b = 2.2 give y = .6x + 2.2. r = .77 says the points rise fairly closely along the line; r² = .6 means the line explains 60% of the spread.

Look for r²=.6 on the screen.

Try it with the keys lit up

This guide is one of E-Code's Learn lessons. Open it on E-Code's TI-84 calculator and each key lights up in turn as you press it.

Try “Show r and r² on a regression” on the TI-84 calculator

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