In this paper, we present a new control chart for exponentially distributed quality characteristics using variable transformation and exponentially weighted moving average (EWMA). The in-control and out-of-control average run lengths (ARLs) are derived using the normal approximation. The parameters of the proposed control chart are determined by considering the target in-control ARL. The efficiency of the proposed control chart is discussed in terms of ARLs over the existing control chart without using EWMA. The application of the proposed control chart is discussed with the help of a real example.
BACKGROUND:
COVID-19 has caused havoc across the globe since, no specific treatment exists for this disease, thus, far. Hence, there is an urgent need to find an effective treatment to mitigate this scourge. Honey and Nigella sativa are two natural substances with anti-inflammatory, anti-viral, anti-microbial and immune modulating properties. They could be potentially beneficial in these patients.
METHODS:
We conducted an add-on, randomized, open label, placebo-controlled clinical trial using parallel group design. This was a multi-centered study with superiority framework conducted in RT-PCR confirmed COVID-19 patients showing moderate or severe disease. All patients receiving standard care were randomized into treatment and control groups. In the treatment arm, patients received HNS (honey plus Nigella sativa) in predefined doses for up to 13 days. The primary outcome measures (time taken for alleviation of symptoms, viral clearance and clinical status improvement on day 6) outcomes were assessed.
RESULTS:
Of 1046 patients testing positive for the SARS-CoV-2, 210 showing moderate and 103 showing severe disease were randomized into treatment and control groups as per inclusion criteria. In the moderate cases, 107 were assigned to the HNS group and 103 to the control group. Among 103 severe cases, 50 were assigned to the HNS group and 53 to the control group. In the moderate and severe cases, the HNS treatment was associated with a normalized median symptoms alleviation time reduction of 3 and 7 days (HR: 6.11; 95% CI: 4.23-8.84 and HR: 4.04; 95% CI, 2.46-6.64) respectively. The HNS treatment in both groups were further associated with 4 days earlier reduction in median viral clearance time (Moderate HR: 5.53; 95% CI: 3.76-8.14) and Severe HR: 4.32; 95% CI: 2.62-7.13). Moreover, in the intention-to-treat analysis, the HNS groups led to a lower (better) clinical score on day 6 with resumption of normal activity among 63.6% of the moderate (OR: 0.07; 95% CI: 0.03-0.13) and 28% of severe cases (OR: 0.03; 95% CI: 0.01-0.09). Furthermore, a significant (14.87%) reduction (OR: 0.18; 95% CI: 0.02-0.92) in mortality was observed in the HNS arm. No difference in adverse effects were seen between the HNS and control arms.
CONCLUSIONS:
A significant reduction in in the severity of disease, the time taken for viral clearance and mortality was observed with HNS treatment in COVID-19 patients. HNS represents a safe, effective, over the counter and affordable therapy for this pandemic essentially lowering health care burden. It can be used alone or in combination with other expensive treatments and give an additive effect. Hence, the potential of HNS against COVID-19 should be explored in future larger studies. (Funded by Smile Welfare Organization, Shaikh Zayed Medical Complex and Services Institute of Medical Sciences; NIH Clinical Trial Register number: NCT04347382.)
In this manuscript a new variable sampling plan based on the exponentially weighted moving average (EWMA) statistic is proposed assuming that the quality characteristic follows the normal distribution. The plans are proposed when the standard deviation of the normal distribution is known or unknown. The plan parameters for both cases are determined such that the given producer's risk and consumer's risk are satisfied. The proposed plan includes the ordinary variable single sampling plan as a special case and its advantage over the single sampling plan is discussed in terms of the sample size. Extensive tables are provided for industrial use.
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