lessR (version 3.5.5)

prob.tcut: Plot t-distribution Curve and Specified Cutoffs with Normal Curve

Description

Plot a specified t-distribution against the standardized normal curve with the corresponding upper and lower tail cutoffs.

Usage

prob.tcut(df, alpha=0.05, dig.dec=3, y.axis=FALSE,
         fill="aliceblue", color.tail="palevioletred4",
         nrm.color=gray(.7), color.t=gray(.08), …)

Arguments

df

Degrees of freedom for t-distribution, must be 2 or larger.

alpha

Alpha to define the tail cutoff area.

dig.dec

Number of decimal digits in the output.

y.axis

If FALSE, then the y axis is not displayed.

fill

Fill color for the interior of the t-distribution curve.

color.tail

Color of the tail areas of the t-distribution.

nrm.color

Color of the normal curve.

color.t

Color of the t-distribution curve.

…

Other parameter values for graphics.

Details

Replaces a t-table by providing the corresponding t-cutoff, the critical value based on the corresponding quantile, as well as a plot that illustrates the tail probabilities. Also compare to the standardized normal curve.

See Also

qt, pnorm.

Examples

# t-distribution with 0.025 cutoffs for degrees of freedom of 15
prob.tcut(15)