alfa: False Alarm probability for the 3-sigma R chart.
Description
Used to calculate the real probability of false alarm in the 3-sigma R chart.
Usage
alfa(n)
Arguments
n
The sample size.
Value
Return the value of the alpha risk for a given sample size n.
Details
This alpha risk is calculated under the exact R statistics distribution and its values for small sample sizes will be much larger than the reference value 0,0027.