Create the confidence bands for a one-sample qq plot — create.qqplot.fit.confidence.interval • BoutrosLab.plotting.general

Returns the values of constructing the confidence bands for a one-sample qq plot

Usage

create.qqplot.fit.confidence.interval(x, distribution = qnorm, conf = 0.95,
    conf.method = "both", reference.line.method = "quartiles");

Arguments

x: A numeric vector
distribution: A quantile function that takes a vector of probabilities as argument and produces the corresponding quantiles from a theoretical distribution, defaults to "qnorm", that is normal distribution.
conf: Confidence level, default to 0.95
conf.method: Methods used to draw confidence bands and must be one of "simultaneous", "pointwise", "both"(default).
reference.line.method: Methods used to draw reference line and must be one of "quartiles"(default), "diagonal", "robust".

Value

Returns the values of creating the upper and lower bands for the qq plot.

Warning

Note that this function works only for a single panel qq plot, not for grouped data and multi-qq plot.

Author

Ying Wu

Examples

tmp.x <- rnorm(100);

tmp.confidence.interval <- create.qqplot.fit.confidence.interval(tmp.x);

qqnorm(tmp.x);
qqline(tmp.x);
lines(tmp.confidence.interval$z, tmp.confidence.interval$upper.pw, lty = 2, col = "brown");
lines(tmp.confidence.interval$z, tmp.confidence.interval$lower.pw, lty = 2, col = "brown");
lines(tmp.confidence.interval$z[tmp.confidence.interval$u], 
    tmp.confidence.interval$upper.sim, lty = 2, col = "blue");
lines(tmp.confidence.interval$z[tmp.confidence.interval$l], 
    tmp.confidence.interval$lower.sim, lty = 2, col = "blue");

legend(1, -1.5, c("simultaneous", "pointwise"), col = c("blue", "brown"), lty = 2, bty = "n");