MSQC::mult.chart ignores xlim argument

I computed Hotelling T2 on a normalized dataset and obtained the following chart in R:

enter image description here

In the chart, I want to study the interval 50-100 in the X-axis closely. Is there any function or method in R through which this can be done? Thanks.

1 answer

  • answered 2019-02-10 13:11 adibender

    Unfortunately, MSQC::mult.chart does not support xlim argument. But you can extract the values to plot and reproduce manually. See example below.

    library(MSQC)
    data(dowel1)
    # default
    mult.chart(dowel1, type = "chi", alpha = 0.05)
    #> [[1]]
    #> [1] "Chi-squared Control Chart"
    #> 
    #> $ucl
    #> [1] 5.99
    #> 
    #> $t2
    #>       [,1]
    #>  [1,] 1.62
    #> ...
    #> 
    #> $Xmv
    #> [1] 0.5 1.0
    #> 
    #> $covariance
    #>         [,1]    [,2]
    #> [1,] 4.9e-05 8.6e-05
    #> [2,] 8.6e-05 4.2e-04
    

    # manual
    mc <- mult.chart(dowel1, type = "chi", alpha = 0.05)
    plot(seq_along(mc$t2), mc$t2, ylim = c(0, mc$ucl), type = "l")
    points(seq_along(mc$t2), mc$t2)
    abline(h = mc$ucl, col = 2)
    

    
    # restricted
    plot(seq_along(mc$t2), mc$t2, ylim = c(0, mc$ucl), type = "l", xlim = c(5, 20))
    points(seq_along(mc$t2), mc$t2)
    abline(h = mc$ucl, col = 2)
    

    Created on 2019-02-10 by the reprex package (v0.2.1)