Below are the solutions to these exercises on “Non-Linear Model in R.” ############### # # # Exercise 1 # # # ############### # load data file Mussel <- read.csv(file.choose()) mussel.nls1 <- nls(SPECIES ~ a * AREA^b, start = list(a = 0.1, b = 1), data = Mussel) summary(mussel.nls1) ## ## Formula: SPECIES ~ a * […]

# non-linear regression

## Non-Linear Models in R: Exercises

A mechanistic model for the relationship between x and y sometimes needs parameter estimation. When model linearisation does not work,we need to use non-linear modeling. There are three main differences between non-linear and linear modeling in R: 1. Specify the exact nature of the equation. 2. Replace the lm() with nls(), which means non-linear least […]

## Polynomial Model in R – Study Case: Solutions

Below are the solutions to these exercises on “Polynomial Models in R – Solutions.” if (!require(car)){install.packages(car, dep=T)} library(car) ############### # # # Exercise 1 # # # ############### # load data file mussel<-read.csv(file.choose()) str(mussel) ## ‘data.frame’: 25 obs. of 3 variables: ## $ AREA : num 516 469 462 939 1357 … ## $ SPECIES: […]

## Polynomial Model in R – Study Case: Exercises

It is pretty rare to find something that represents linearity in the environmental system. The Y/X response may not be a straight line, but humped, asymptotic, sigmoidal or polynomial are possibly, truly non-linear. In this exercise, we will try to take a closer look at how polynomial regression works and practice with a study case. […]