Cosmed Quark PFT, Manual

Page: 101 / 148

Chapter 12 - Exercise Testing - 101
Fittings
The purpose of the fitting function is to find the function that fits as better as possible
the measured data.
The software allows to fit data according to 3 different functions:
Model Function Algorithm Available for
Linear Y=A*X+B Least squares Any Y vs any X graph
Mono-Exp Y=A+B*exp[(t-t
0
)/tau] Levemberg Marquardt Any Y vs Time Graph
Mean value
This function is available only if the active window is a single Y graph (i.e. VO
2
vs time
or VO
2
vs Load).
Fit a graph with a linear regression
1. Make active the graph window (any Y vs any X graph).
2. Right-click and select
Fitting.
3. Choose Linear in the type combo box
4. Select the first point ( X1 ) moving the mouse on the desired place in the graph
pressing the Left key or using the + and – keys.
5. Select the second point ( X2 ) moving the mouse on the desired place in the graph
pressing the Right key or using the + and – keys.
6. Press OK to confirm.
Fit a graph with a Mono-exponential regression
1. Make active the graph window (any Y vs any X graph).
2. Right-click and select
Fitting.
3. Choose Mono-exponential in the type combo box
4. Select the first point ( X1 ) moving the mouse on the desired place in the graph
pressing the Left key or using the + and – keys.
5. Select the second point ( X2 ) moving the mouse on the desired place in the graph
pressing the Right key or using the + and – keys.
6. Enter (if necessary) the initial values of A, B and TAU (these are the values from
which the iterative algorithm starts in order to reach the best values; the closer are
the initial coefficients to the best ones the higher is the possibility to reach the best
fit).
7. Press OK to confirm.