How to Find the Slope and the Intercept with the Casio fx-991ES PLUS (linear regression)

To calculate the slope and the intercept all you need is to follow these steps:

  1. Press mode and the 3 to choose STAT mode.
  2. Press 2 for A+BX ( equivalent to y = mx + c or y = mx + b or y = kx + m or y = ax + b )
  3. Enter you data points (example below)
  4. Press AC (orange)
  5. Press “SHIFT” and the key 1
  6. Press the key 5
  7. Press the key 1 for A (intercept)
  8. Repeat steps 5 and 6 and press the key 2 for B (slope)
    Scroll down for the linear equation of the table below.
X Y
1.00 0.18
1.70 0.24
2.50 0.31
5.00 0.41
20.00 0.53

f(x)= 0.0155x+0.24

To calculate the standard deviation to for x (sx) and y (sy)

  1. Press SHIFT and the key 1
  2. Press the key 4
  3. Press the key 4 or 7 for the sx and the sy accordingly

Source fx-991ES PLUS User’s Guide

Related to Enzyme Kinetics (Michaelis-MentenFormula) and Lineweaver-Burke diagram