pnormGC function

Graphical Calculator for Normal Curve Probabilities

Shades desired areas under a specified normal curve, returns numerical value of the area.

pnormGC(bound,region="below",mean=0,sd=1,graph=FALSE)

Arguments

• bound: A numerical vector of length 1 or 2, indicating the boundary (respectively, boundaries) of shaded region on the bhorizontal axis
• region: A character string. Default is "below". Possible values are "between" (when boundary consists of two numbers), "below", "above", and "outside" (again when boundary consists of two numbers)
• mean: Mean of the distribution
• sd: Standard deviation of the distribution
• graph: Will produce graph of the probability

Returns

Numerical value of area under curve over region.

Examples

#This gives P(X < 75) for X normal with mean=70 and sd=4:
pnormGC(75,region="below",mean=70,sd=4)

#This gives P(X > 71) for X normal with mean=70 and sd=4:
pnormGC(71,region="above",mean=70,sd=4)

#This gives P(-1 < X < 1), for standard normal X:
pnormGC(c(-1,1),region="between")

#This gives P(X < 68 or X > 71), for X normal with mean =70 and sd=4:
pnormGC(c(68,71),region="outside",mean=70,sd=4)

Author(s)

Homer White hwhite0@georgetowncollege.edu