Browsing by Author "Prabhakar Mishra"

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A note on the estimators for coefficient of dispersion using auxiliary information
(Bellwether Publishing, Ltd., 2020) Rajesh Singh; Gautam Kumar Vishwakarma; Prabhakar Mishra
Ambati et al. (2017) proposed an estimator for estimating the unknown coefficient of dispersion under simple random sampling without replacement case. Erroneously, the mean squared error (MSE) expression obtained by Ambati et al. (2017) was incorrect. In this paper, we have obtained correct expression of the MSE of the estimators proposed by Ambati et al. (2017). A simulation study is carried out to demonstrate the theoretical results empirically. © 2019 Taylor & Francis Group, LLC.
Estimation of population coefficient of dispersion using auxiliary information in simple random sampling
(American Institute of Physics Inc., 2023) Prabhakar Mishra; Madhulika Mishra; Rajesh Singh
It is a well-established fact in sampling survey theory that using auxiliary information during the estimation stage aids in increasing the precision of estimator for unknown population parameter. Averages or measures of central tendency give us an idea about the concentration of objects around the central value of the distribution. However, if we want to have insights regarding the scatteredness of the observations around the central values, we would have to study about dispersion. One of the techniques of measuring dispersion is through coefficients of dispersion. An enormous amount of work has been already done for the problem of estimation of population mean, median, mode, variance, coefficient of variation etc. However not much attention has been given to the problem of estimation of coefficient of dispersion. In this manuscript, we contemplate the problem of estimation of population coefficient of dispersion under SRSWOR using a single auxiliary variable. We have obtained the expression for MSE of the proposed estimators under the first order of approximation. Also, we have incorporated a simulation study to verify the theoretical results. © 2023 Author(s).
ESTIMATION OF POPULATION VARIANCE IN LOG - PRODUCT TYPE ESTIMATORS UNDER DOUBLE SAMPLING SCHEME
(River Publishers, 2019) Prabhakar Mishra; Rajesh Singh; Supriya Khare
It is experienced that auxiliary information when suitably incorporated yields more efficient and precise estimates. Mishra et al. (2017) have introduced a log type estimator for estimating unknown population mean using ancillary information in simple random sampling. Here we propose an improved log-product type estimator for population variance under double sampling. Properties of the estimators are studied both mathematically and numerically. © 2019 Journal of Reliability and Statistical Studies. All rights reserved.
EXPONENTIAL TYPE ESTIMATOR FOR MISSING DATA UNDER IMPUTATION TECHNIQUE
(Universidad de La Habana, 2022) Rajesh Singh; Prabhakar Mishra; Ahmed Audu; Supriya Khare
In this paper, we suggest an exponential type estimator for estimation of population mean for missing data under suggested imputation techniques. Family of proposed estimator is obtained for missing data. Expression for Bias and MSE’s are acquired in the form of population parameters up to the terms of first order of approximation. Theoretical results depict the superiority of proposed estimator and its family over other estimators. The empirical study in support of theoretical results is also included to verify the results numerically. © 2022 Universidad de La Habana. All rights reserved.
Log-Product-Type Estimator for Estimation of Population Variance Using Auxiliary Information
(Thai Statistical Association, 2024) Prabhakar Mishra; Ashish Sharma; Nitesh Kumar Adichwal; Sakshi Rai; Rajesh Singh
This paper proposed a log product type estimator for estimating population variance under simple random sampling without replacement (SRSWOR) using auxiliary information. We have calculated the mean square error (MSE) and bias expressions up to the first order of approximation. To substantiate the result, an empirical study has been performed using three real population data sets. The properties of the estimators also verified through simulation study. The result shows that the performance of the proposed estimator is better than the existing estimators. © 2024, Thai Statistical Association. All rights reserved.
Rest or 30-Min Walk as Exercise Intervention (RESTOREX) in Myasthenia Gravis: A Randomized Controlled Trial
(S. Karger AG, 2021) Usha K. Misra; Jayantee Kalita; Varun K. Singh; Aditya Kapoor; Abhilasha Tripathi; Prabhakar Mishra
Introduction: There is a lack of evidence about the usefulness of exercise or rest in myasthenia gravis (MG). This study is aimed to evaluate the efficacy and safety of exercise or rest in MG. Methods: In a single-center open-labeled randomized controlled trial, the patients with mild to moderate MG were randomized to 30-min walk or rest in addition to the standard treatment. The primary endpoint was 50% improvement in the MG Quality of Life (MG-QOL15), and secondary endpoints were change in the Myasthenic Muscle Score (MMS), MG Activities of Daily Living (MGADL), grip strength, dose of acetylcholine esterase inhibitor and prednisone, 6-min walk test (6MWT), decrement in trapezius on the low-rate repetitive nerve stimulation test, and adverse events. The outcomes were defined at 3 months, by >50% improvement in these outcome parameters. Results: Forty patients with MG were randomized to the exercise or rest arm. The 2 arms were matched for demographic and clinical parameters. The patients in the exercise arm had significantly better QOL evidenced by MG-QOL15 (p = 0.02). The secondary endpoints, distance covered in 6MWT (p = 0.007), were also better in the exercise arm without any adverse event. Conclusion: Regular exercise for 30 min in mild and moderate MG improves quality of life and walking distance compared to rest and is safe. Clinical Trial Registration: The clinical trial registration number is CTRI/2019/11/021869. © 2021 S. Karger AG, Basel. Copyright: All rights reserved.