| reg {pad} | R Documentation |
These functions takes arguments defining a regression model with one or two explanatory variables and plots the data, regression model and residuals.
reg(n.expl, ...)
reg1(true.model, n.points, range.x, regular, x, ...)
reg2(true.model, n.points, range.x1, range.x2,
regular, x1, x2, ...)
n.expl |
the number of explanatory variables. The only values allowed are 1 or 2. |
true.model |
a equation defining the true regression model.
Examples of specifications are: 2 + 3*x for one explanatory variable and 3 + 2*x1 - 3*x2 for two explanatory variables |
range.x, range.x1, range.x2 |
a two elements numerical vector with minimum and maximum values for the explanatory variable |
n.points |
number of data points |
regular |
logical. TRUE (the default) indicates that values of the
explanatory variable will be regularly spaced between the range of
x. FALSE means that values of x will be sampled in the range of x |
x, x1, x2 |
objects (vector) or keyboard input with values of the
explanatory variable(s). Only used if range.x and
range.y are not provided. |
... |
further arguments to be passed to the plot function |
The main function reg asks for the number of explanatory
variables and then
calls reg1 or reg2 for the
case of one or two respectively.
The function takes a ``true'' model and values for the explanatory variable(s) and build the response variable from this, adding to the response variable an error with variance equivalent to 20% of its variance.
A linear regression model is fitted and results are displayed in the graphical device.
The function reg1 produces a 2D plot with data against
the explanatory variable and adds a line with the fitted regression
model.
If the packages scatterplot3d is available,
the function reg2 produces a 3D plot with data against the
explanatory variables
and adds a plane with the regression model fitted to the data.
In both cases a second plot with residuals against fitted value is produced.
Peter J. Diggle p.diggle@lancaster.ac.uk
Paulo Justiniano Ribeiro Jr. p.ribeiro@lancaster.ac.uk.
reg(1, "1 + 3*x", n.p = 21, range.x = c(0,20), reg = TRUE)
reg(1, "1 + 3*log(x^2)", n.p=25, range.x = c(1, 100), reg=TRUE)
reg(1, "10 - 2*exp(-x/10)", x = 1:30)
##
reg(2, "10 - 5*x1 + 3*x2" , x1 = runif(25), x2 =runif(25))
reg(2, "1+ 3*sqrt(x1) -2*x2^2" , n.p=50, range.x1=c(10, 30),
range.x2 =c(1, 5))
#
# For an interactive input type:
## Not run:
reg()
## End(Not run)