UchartI {IQCC} | R Documentation |
This function builds the traditional Shewhart u chart based on normal approx. for the Poisson-based count data statistic . It is designed for phase I.
UchartI(x, sizes, par, length)
x |
The data to be plotted. |
sizes |
A value or a vector of values specifying the sample sizes associated with each group. |
par |
The sample ratios used to estimate the Poisson parameter(lambda). |
length |
The length of the data. |
It is important to note that the normal approx. involved is valid only for n.p large. For small n.p , it should be used an "improved u chart" (with non-normal correction) given by the function "UextI" for phase-I or "UextII" for phase II .
Return a traditional U control chart.
Daniela R. Recchia, Emanuel P. Barbosa
data(moonroof) attach(moonroof) UchartI(par=ui[1:17],x=yi[1:17],sizes=ni[1:17],17)