trendscatter: Trend and scatter plot

In s20x: Functions for University of Auckland Course STATS 201/208 Data Analysis

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, ...)

## Default S3 method:
trendscatter(x, y = NULL, f = 0.5, xlab = NULL, ylab = NULL, main = NULL, ...)

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

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.

Value

Returns the plot.

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))

s20x documentation built on Aug. 21, 2023, 5:07 p.m.