Normal Tail Probability — iscamnormprob • ISCAM

normprob finds a p-value and plots it onto a normal distribution with mean and standard deviation as specified. The function can find the probability above, below, between, or outside of the observed value, as specified by directions.

Usage

iscamnormprob(
  xval,
  mean = 0,
  sd = 1,
  direction,
  label = NULL,
  xval2 = NULL,
  digits = 4
)

Arguments

xval: observed value.
mean: mean of normal distribution.
sd: standard deviation of normal distribution.
direction: direction for probability calculation, "above" or "below"; if "outside" or "between" are used, a second larger observation, xval2 must be specified
label: horizontal axis label.
xval2: second observation value.
digits: number of digits to display.

Value

a p-value and a plot of the normal distribution with shaded area representing probability of the observed value or more extreme occurring.

Examples

iscamnormprob(1.96, direction = "above")

#> probability: 0.025 
#> [1] "0.025"
iscamnormprob(-1.5, mean = 1, sd = 2, direction = "below")

#> probability: 0.1056 
#> [1] "0.1056"
iscamnormprob(0, xval2 = 1.5, direction = "between")

#> probability: 0.4332 
#> [1] "0.4332"
iscamnormprob(-1, xval2 = 1, direction = "outside")

#> probability: 0.3173 
#> [1] "0.3173"