qgnormz: Graphical display for a Standard Normal distribution, given a...

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

Graphical display for a Standard Normal distribution, given a specified tail probability

Description

A function to draw a Standard Normal distribution and shade the region(s) defined by the probability argument

Usage

qgnormz(prob, tail = "upper")

Arguments

prob

prob is the tail probability value to define the region to be shaded on the graph and the corresponding quantile to be displayed. note that if tail="two", this probability is halved for display in each tail.

tail

Area(s) to be shaded on the graph. If "upper", the function returns a graph with the upper tail area shaded and the upper tail probability displayed. If "lower", the function returns a graph with the lower tail area shaded and the lower tail probability displayed. If "two" the function returns a graph with both tails shaded and the specified probability is halved between these two tails. tail="upper" is the default.

Warning

Specifying extremely high or low probabilities may not yield visible shaded areas if the regions are beyond the limits of the X axis scale of the graph.

Note

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

Author(s)

Bruce Dudek [e-mail]

Examples

qgnormz(.35) #shows upper tail by default
qgnormz(.16,tail="upper")
qgnormz(.16,tail="lower")
qgnormz(.975,tail="lower")
qgnormz(.025,tail="upper")

bcdudek/bcdstats documentation built on Aug. 15, 2024, 7:24 p.m.