Dawnbridge

Casio fx-CG50 field manual for IB Math

Everyone · 23 of 44

23

Exponential regression

All courses

Fit y=a⋅bx to paired data and read the fitted parameters.

Goal

Fit an exponential model to ​(0,5),  ​(1,8),  ​(2,11),  ​(3,20),  ​(4,31).

1

From the MAIN MENU, open Statistics. If you're already inside another app, press first to get back to MAIN MENU.

2

Enter the ​x​-values 0, 1, 2, 3, 4 in List 1 and the ​y​-values 5, 8, 11, 20, 31 in List 2. Press after each entry.

RadNorm2
d/cReal
List 1List 2List 3List 4SUB105218321143205431
GRAPHCALCTESTINTRDIST▷
3

Press (CALC), then (SET) and set 2Var XList = List1, 2Var YList = List2, 2Var Freq = 1, then . Press (REG), then (▶) to reach the second strip, then (EXP) and (ab^x). The ​a⋅ebx​ variant sits on .

RadNorm2
d/cReal
ExpReg(a·b^x)
a=4.90483267
b=1.57860087
r=0.99662371
r²=0.99325883
MSe=4.7153×10-03
y=a·b^x
COPY
Result

The calculator uses the form ​y=a⋅bx, so the model is ​y≈4.90(1.58)x, with ​r≈0.997.

Your turn

Work each one on your calculator, then check the answer.

  1. 1

    Fit an exponential model ​y=a⋅bx​ to ​(0,4),  ​(1,6),  ​(2,10),  ​(3,15).

  2. 2

    Fit an exponential model to the (noisy) data ​(0,3.1),  ​(1,4.1),  ​(2,6.0),  ​(3,8.1).

  3. 3

    Fit an exponential model to ​(0,80),  ​(1,63),  ​(2,52),  ​(3,41),  ​(4,33).