Title

     dftolss -- Sample size calculation for distribution-free tolerance
                    intervals

Syntax

        dftolss , [conf(#) beta(#) r(#)]

    options       Description
    -------------------------------------------------------------------------
      conf(#)     set confidence level of the tolerance interval; default is
                    conf(95)
      beta(#)     set percentage of the population covered by the tolerance
                    interval; default is beta(95)
      r(#)        set the number of blocks removed; default is r(2)
    -------------------------------------------------------------------------

Description

    dftolss computes the smallest sample size for the tolerance intervals
    obtained removing r(#) blocks to contain, at confidence level conf(#)%,
    at least a percentage beta(#)% of the sampled population. See also dftol.

Remarks

    dftolss requires that the Stata module -moremata- (Jann, 2005) be
    installed.

Options

    conf(#) specifies the confidence level of the tolerance interval as a
        percentage. The default is conf(95), meaning a 95% confidence level.

    beta(#) specifies the percentage of the sampled population to be
        contained in the tolerance interval. The default is beta(95), meaning
        a percentage equal to 95%.

    r(#) specifies the number of blocks removed. The default is r(2), which,
        according to the definition of block (see Murphy, 1948) means that
        the endpoints of the tolerance interval would be the smallest and
        largest observations of the sample. Note that for r(1), i.e. when
        only one block is removed, the interval reduces to a one-sided lower
        (alternatively, upper) tolerance bound.

Examples 

 . dftolss
 . dftolss, c(90) b(90)
 . dftolss, c(99) b(99) r(4)

Saved results

dftolss saves the following in r():

Scalars

    r(n)           sample size)

Author

    Ignacio López de Ullibarri
    Department of Mathematics
    University of A Coruña, Spain
    E-mail: ilu@udc.es

References

    Jann B (2005), moremata: Stata module (Mata) to provide various
        functions, available from 
        http://ideas.repec.org/c/boc/bocode/s455001.html

    Murphy RB (1948), Non-parametric tolerance limits, Annals of Mathematical