distplot {vcd} | R Documentation |
Diagnostic distribution plots: poissonness, binomialness and negative bionomialness plots.
distplot(obj, type = c("poisson", "binomial", "nbinomial"), size = NULL, lambda = NULL, legend = TRUE, ylim = NULL, line.col = 2, conf.int = TRUE, conf.level = 0.95, main = NULL, xlab = "Number of occurrences", ylab = "Distribution metameter", ...)
obj |
either a vector of counts, a 1-way table of frequencies of counts or a data frame or matrix with frequencies in the first column and the corresponding counts in the second column. |
type |
a character string indicating the distribution. |
size |
the size argument for the binomial distribution, only
required if type is "binomial" . If set to NULL ,
size is taken to be the maximum count. |
lambda |
parameter of the poisson distribution. If type is
"poisson" and lambda is specified a leveled
poissonness plot is produced. |
legend |
logical. Should a legend be plotted?. |
ylim |
limits for the y axis. |
line.col |
color for fitted line. |
conf.int |
logical. Should confidence intervals be plotted?. |
conf.level |
confidence level for confidence intervals. |
main |
a title for the plot. |
xlab |
a label for the x axis. |
ylab |
a label for the y axis. |
... |
further arguments passed to plot . |
distplot
plots the number of occurrences (counts) against the
distribution metameter of the specified distribution. If
the distribution fits the data, the plot should show a
straight line. See Friendly (2000) for details.
Achim Zeileis
D. C. Hoaglin (1980), A poissonness plot, The American Statistican, 34, 146-149.
D. C. Hoaglin & J. W. Tukey (1985), Checking the shape of discrete distributions. In D. C. Hoaglin, F. Mosteller, J. W. Tukey (eds.), Exploring Data Tables, Trends and Shapes, chapter 9. John Wiley & Sons, New York.
Michael Friendly (2000), Visualizing Categorical Data. SAS Institute, Cary, NC.
## Simulated data examples: dummy <- rnbinom(1000, size = 1.5, prob = 0.8) distplot(dummy, type = "nbinomial") ## Real data examples: data(HorseKicks) data(Federalist) data(Saxony) distplot(HorseKicks, type = "poisson") distplot(HorseKicks, type = "poisson", lambda = 0.61) distplot(Federalist, type = "poisson") distplot(Federalist, type = "nbinomial") distplot(Saxony, type = "binomial", size = 12)