s20x (version 3.1-40)

trendscatter: Trend and scatter plot

Description

Plots a scatter plot for the variables x, y along with a lowess smooth for the underlying trend. One standard deviation error bounds for the scatter about this trend are also plotted.

Usage

trendscatter(x, ...)
# S3 method for default
trendscatter(x, y = NULL, f = 0.5, xlab = NULL, ylab = NULL, main = NULL, ...)
# S3 method for formula
trendscatter(
  x,
  f = 0.5,
  data = NULL,
  xlab = NULL,
  ylab = NULL,
  main = NULL,
  ...
)

Value

Returns the plot.

Arguments

x

the coordinates of the points in the scatter plot. Alternatively, a formula.

...

Optional arguments

y

the y coordinates of the points in the plot, ignored if x is a function.

f

the smoother span. This gives the proportion of points in the plot which influence the smooth at each value. Larger values give more smoothness.

xlab

a title for the x axis: see title.

ylab

a title for the y axis: see title.

main

a title for the plot: see title.

data

an optional data frame containing the variables in the model.

Methods (by class)

• trendscatter(default): Trend and scatter plot

• trendscatter(formula): Trend and scatter plot

See Also

residPlot

Examples

# A simple polynomial
x = rnorm(100)
e = rnorm(100)
y = 2 + 3 * x - 2 * x^2 + 4 * x^3 + e
trendscatter(y ~ x)

# An exponential growth curve
e = rnorm(100, 0, 0.1)
y = exp(5 + 3 * x + e)
trendscatter(log(y) ~ x)

# Peruvian Indians data
data(peru.df)
trendscatter(BP ~ weight, data = peru.df)

# Note: this usage is deprecated
with(peru.df,trendscatter(weight,BP))