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

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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, digits_d=3, y_axis=FALSE,
         fill="aliceblue", color_tail="palevioletred4",
         nrm_color=gray(.7), color_t=gray(.08),
         pdf_file=NULL, width=5, height=5, ...)

Arguments

df	Degrees of freedom for t-distribution, must be 2 or larger.
alpha	Alpha to define the tail cutoff area.
digits_d	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.
pdf_file	Name of the pdf file to which graphics are redirected.
width	Width of the pdf file in inches.
height	Height of the pdf file in inches.
...	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.

Value

cutoff: Cutoff-value, the corresponding quantile.

Author(s)

David W. Gerbing (Portland State University; [e-mail])

See Also

qt, pnorm.

Examples

# t-distribution with 0.025 cutoffs for degrees of freedom of 15
prob_tcut(15)

lessR documentation built on Nov. 12, 2023, 1:08 a.m.