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STS540 J.-C. Malela-Majika et al.

Figure 4. The BTXII X control schemes versus the traditional X control
schemes (IRR2-of-(h+1) schemes for different values of ℎ) under zero-
state and steady-state modes when n = 5 and 10

4. Discussion and Conclusion
We considered the SS 2-of-(ℎ + 1) and 1-of-1 or 2-of-(ℎ + 1) schemes to
expand the Shewhart-type scheme for non-normal distributed data using
̅
the BTXII distribution under the assumption that the process parameters are
known (Case K). The zero-state and steady-state performances are
investigated using the Markov chain approach.
It was observed that the proposed schemes outperform the traditional
ones, and present very interesting run-length characteristics under the
normal and non-normal distributions. Moreover, the proposed side-sensitive
schemes outperform the NSS schemes proposed by Malela-Majika, Kanyama
and Rapoo (2017). For small to moderate shift we recommend using the SS

SRR2-of-(h+1) schemes and for large shifts we recommend using the SS IRR2-of-
(h+1) schemes. The case where the process parameters are unknown and need
to be estimated are currently under investigation.

5. Acknowledgement
Marien Graham’s research was funded by the National Research
Foundation (NRF) [reference: PR_IFR190111407337, UID: 114814]

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