qgf: Graphical display for the F distribution, given a specified...

In bcdudek/bcdstats: A collection of functions to support B. Dudek's APSY510/511 classes

Graphical display for the F distribution, given a specified probability

Description

A function to produce a graph of an F distribution with regions shaded according to a specified probability.

Usage

qgf(prob, df1 = 1, df2 = 5)

Arguments

prob	The upper tail probability value to define the region to be shaded on the graph and the corresponding quantile to be displayed.
df1	Numberator degrees of freedom for the F distribution. Note that the default is 1.
df2	Numberator degrees of freedom for the F distribution. Note that the default is 25.

Warning

Specifying extremely small probabilities may not yield visible shaded areas if the quantile is in a region of the graph where the density approaches zero.

Note

This function can be very helpful in instructional situations and can replace the "F table" from textbooks.

Also note that the qgf function only displays upper tail regions since most inference with the F distribution only requires upper tail evaluation. The lower tail probability is 1 minus the returned value.

Author(s)

Bruce Dudek [e-mail]

Examples

qgf(.05,df1=1,df2=25)
qgf(.05,df1=6,df2=80)
qgf(.35,df1=1,df2=25)
qgf(.01,df1=3,df2=32)

bcdudek/bcdstats documentation built on Jan. 3, 2024, 10:09 p.m.