qpcR (version 1.4-1)

Rsq: R-square value of a fitted model

Description

Calculates the \(R^2\) value for objects of class nls, lm, glm, drc or any other models from which fitted and residuals can be extracted. Since version 1.2-9 it calculates a weighted \(R^2\) if the object has an item object$weights containing weighting values.

Usage

Rsq(object)

Arguments

object

a fitted model.

Value

The \(R^2\) value of the fit.

Details

Uses the most general definition of \(R^2\): $$R^2 \equiv 1 - \frac{RSS}{TSS}$$ where $$RSS = \sum_{i=1}^{n}w_i \cdot (y_i-\hat{y}_i)^2$$ and $$TSS = \sum_{i=1}^{n}w_i \cdot (y_i - \bar{y})^2$$ using the weighted mean $$\bar{y} = \frac{\sum_{i=1}^{n}w_ix_i}{\sum_{i=1}^{n}w_i}$$

Examples

# NOT RUN {
m1 <- pcrfit(reps, 1, 2, l5)
Rsq(m1)   
# }