# Function to plot t2 Hotelling chart

### Description

This function is used to compute statistics required by the t2 chart.

### Usage

1 2 3 4 5 6 7 8 9 10 11 | ```
mqcs.t2(x, ...)
## Default S3 method:
mqcs.t2(x, data.name = NULL, limits = NULL, Xmv = NULL,
S = NULL, colm = NULL, alpha = 0.01, phase = 1, method = "sw",
plot = FALSE, ...)
## S3 method for class 'mqcd'
mqcs.t2(x, limits = NULL, Xmv = NULL, S = NULL,
colm = NULL, alpha = 0.01, phase = 1, method = "sw", plot = FALSE,
...)
``` |

### Arguments

`x` |
an R object (used to select the method). See details. |

`...` |
arguments passed to or from methods. |

`data.name` |
a string that specifies the title displayed on the plots. If not provided it is taken from the name of the object's data. |

`limits` |
a two-values vector specifying the control limits. |

`Xmv` |
is the mean vector. It is only specified for Phase II or when the parameters of the distribution are known. |

`S` |
is the sample covariance matrix. It is only used for Phase II or when the parameters of the distribution are known. |

`colm` |
is the number of samples (m) and it is only used in Hotelling control chart for Phase II |

`alpha` |
it is the the significance level (0.01 for default) |

`phase` |
Allows to select the type of UCL to use. Only values of phase = 1 or 2 are allowed. |

`method` |
is the method employed to compute the covatiance matrix in the individual observation case. Two methods are used "sw" for compute according to (Sullivan,Woodall 1996a) and "hm" by (Holmes,Mergen 1993) |

`plot` |
a logical value indicating that it should be plotted. |

### Author(s)

Edgar Santos-Fernandez

### Examples

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | ```
##
## Continuous data
##
library(qcr)
data(dowel1)
str(dowel1)
data.mqcd <- mqcd(dowel1)
res.mqcs <- mqcs.t2(data.mqcd)
summary(res.mqcs)
plot(res.mqcs, title =" Hotelling Control Chart for dowel1")
data(archery1)
str(archery1)
data.mqcd <- mqcd(archery1)
res.mqcs <- mqcs.t2(data.mqcd)
summary(res.mqcs)
plot(res.mqcs, title =" Hotelling Control Chart for archery1")
``` |