Department of Statistics

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Author: search.filters.author.Dr. Riffat Jabeen

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    Control Charts for new Reflected Pareto Distribution
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) Huma Khalid; FA19-RST-007; Dr. Riffat Jabeen; LHR TP 7203
    Pareto distribution has vast application in different fields of medical and engineering sciences. In this thesis, we have proposed a new Reflected Pareto Distribution (RPD) using Cohen (1973) to reflect the parameter of distribution. We derive different mathematical properties such as mean, variance, rth moment. Reliability measures are also discussed including Survival Function, Hazard function and reversed hazard function. The method of Maximum Likelihood Estimator and Modified maximum likelihood estimator is used to estimate the model parameters. We used three different data sets to show the performance of Reflected Pareto distribution over already existing probability distributions. We also construct the control charts to monitor the shape parameter for reliability processes using Shewhart control chart and Exponentially weighted moving averages control chart. We compare the performance of maximum likelihood estimator and modified maximum likelihood estimator for the shape parameter of Reflected Pareto distribution.
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    Development of Estimators for Population Mean of Sensitive Variable in Survey Sampling
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2017) Muhammad Kamran ASLAM; SP16-RST-005; LHR TP 4833; Dr. Riffat Jabeen
    In Chapter 1, introduction about Survey sampling, use of auxiliary in formation in context stratified random sampling has been deliberated. Further in Chapter 1, Different methods dealing randomized response have been deliberated by different authors but Hansen-Hurwitz sub sampling has been consider in more detail. In Chapter 2, the literature regarding the use of classical sampling de sign has been deliberated. The literature about some existing estimators for calibration estimator under stratified random sampling has been ex press. Various work of randomized response has also been specified in Chapter 2. Some well-known existing randomized response model, scrambling vari able under auxiliary and study variable, with randomized response or complete response have been reproduced in Chapter3. The major con tribution of this study starts from next Chapter. In Chapter 4, new estimators using auxiliary information have been proposed for calibration estimator in randomized response under strat ified random sampling scheme. The mean square error each estimator has been derived along. In Chapter 5 conclusion has been drawn about the generalized class of estimators proposed in this study. Finally it is shown that the propose estimator II is more efficient than proposed estimator I.
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    CRESCENT BAHUMAN LIMITED
    (Library Information Services COMSATS University Islamabad Lahore Campus, 2024-04-02) Maydah Azhar; FA20-BST-008; Dr. Riffat Jabeen
    Bahaman Limited. The purpose of this report is to demonstrate the practical application of my academic knowledge and skills in a real-world business setting. With more than 60 years of experience in industries as diverse as textiles, sugar, banking, insurance, food, agriculture and steel, Crescent Group has built a solid reputation in Pakistan's business community. Crescent Bahaman was initially formed as a joint venture between Crescent Group and Greenwood Mills. It has been wholly owned by the Crescent Group since 2001. In FY21, the Pakistan's commodities expanded by 14% insufferable from a low-base impact, coming about because of the pandemic prompted lockdown in 2020. By and large, the figures of commodities stay inside the scope of USD 22-25b, which is in accordance with the pattern of past ten years. The portion of materials in complete products has generally been 54-59%; coming in at 57% during FY21. The low-base impact was articulated in material area also, with the post-lockdown increase of around 13% in the products. Pakistan's material commodities have CAGR of 4.4% during long term period from FY19 to FY21. Inside the materials, high worth added fragment held the most extreme offer, which has been moving vertically or most recent three years, expanding from 73.9% in FY19 to 80.7% in FY21. Knitwear, readymade pieces of clothing, and bed wear comprise the significant part of this portion.
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    INTERNSHIP REPORT ON BAIG ELECTRICAL COMPANY (PVT.) LIMITED
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Fakhra Manzoor; CIIT/FA21-BST-009/LHR; Dr. Riffat Jabeen; LHR TP 9957
    When I was working as an intern in Baig Electrical Company (Pvt.) Ltd., I was blessed to work with an organization that was electrical based and I was able to develop on several of these skills. The type of tasks included data entry and auditing; in this way, I gained knowledge of the finance department. The management practices that were explained to me were useful in realizing that people have various responsibilities within a firm. I have appreciated various aspects of how a business runs and the many roles I can take on depending on the sector. In the course of my internment, I engaged myself with multiple exercises that were entirely a new and unique experience to me. They allowed me to participate in testing processes, which provided me with practical experience that I needed. I also came to appreciate quality assurance and got to deal with transformers and switch gears, which I found out are among the company’s biggest brands in the market. This exposure has given me this information on the competition in the electrical sector. I understood the importance of product quality and safety standards in situation to the electrical field which are the critical factor of electrical products and systems’ reliability and safety. It equipped me with technical know-how in and out, soft skills as a team player, good communicator and critical thinker.
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    A study of ordered random variables for Reflected Power Function Distribution
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2024) Maydah Azhar; CIIT/FA20-BST-008/LHR; Dr. Riffat Jabeen; LHR TP 9953
    This thesis presents a comprehensive study of ordered random variables for the Reflected Power Function Distribution (RPFD). The primary focus is on the statistical properties, parameter estimation methods, and applications of the RPFD. The RPFD is a transformation of the traditional Power Function Distribution, which is frequently used to model phenomena in various fields such as hydrology, economics, and engineering. By reflecting the distribution around its midpoint, the RPFD provides a mirrored perspective that is particularly useful for scenarios where probabilities are skewed in the opposite direction. The study begins with an introduction to the Power Function Distribution and its reflection to form the RPFD. The properties of the RPFD, including its probability density function, survival function, hazard rate function, and moments, are thoroughly explored. Various parameter estimation techniques such as Maximum Likelihood Method (MLM), Modified Maximum Likelihood Method (MMLM), and percentile-based estimators are discussed in detail. Furthermore, the thesis delves into generalized order statistics (GOS) and their specific application to the RPFD. This includes the derivation of the probability density function (PDF) and joint PDF for GOS, as well as the calculation of mean, variance, and covariance for different scenarios. The literature review highlights key studies and methodologies that have contributed to the development and understanding of order statistics and RPFD. Empirical analysis using real-life data sets demonstrates the practical utility and superior performance of the RPFD compared to other models. Overall, this research contributes to the statistical theory by providing new insights and tools for the application of the RPFD in various scientific and engineering disciplines.
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    Development Of Calibration Log Estimator to Estimate Population Mean Using Randomized Response Technique
    (Library Information Services, COMSATS University Islamabad, Lahore Campus., 2020-04-01) Rehmina; CIIT/FA19-BST-011/LHR; Dr. Riffat Jabeen; LHR TP 9944
    Calibration method is a useful method in daily life meanwhile it allows us to gather a single sample without repeating the process. In the presence of sensitive information, we calculate the variation of population with the help of calibration method. We proposed calibration log ratio estimator by using the method of (Jabeen, et al. 2022) in the presence of sensitive data.
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    Construction of Calibration Log Ratio Estimator to Estimate Population Variance
    (Library Information Services, COMSATS University Islamabad, Lahore Campus., 2020-04-01) Khafiza Afzal; CIIT/FA19-BST-003/LHR; Dr. Riffat Jabeen; LHR TP 9938
    Calibration is frequently used to improve the population parameter estimation’s accuracy using auxiliary data. In our study, we have introduced the calibration and the calibration log variance estimator for estimating the population variance. The study proposes the calibration variance log estimators using chi square distance measure and different calibration constraints respectively. Our findings indicate that the suggested calibration variance estimator performed better than the existing estimator.
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    Some Memory Type Estimators for Population Variance in Survey Sampling
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Umme Habiba; CIIT/FA23/RST/004/LHR; Dr. Riffat Jabeen; LHR TP 9874
    Reducing and estimating population variation is important in survey sampling. These variations can occur in any sampling design, including stratified random sampling. In stratified random sampling the difference in stratum weights increase the variation. This problem can be control with the use of calibration techniques, and auxiliary information. By using this technique, we can increase the accuracy and efficiency of estimator. Improving the efficiency of estimator for population variance estimation is the primary goal of this study. Both exponentially weighted moving average (EWMA) and extended exponentially weighted moving average (EEWMA) memory type statistics are used in this study to estimate population variance. EWMA use only current data whereas EEWMA use both current and past observations. The EWMA and EEWMA statistics are used to build the calibration variance and ratio estimators. The mean square errors are calculated, and the effectiveness of the estimators is illustrated through a discussion of mathematical comparisons. To assess the efficiency of the proposed memory type estimators, a simulation study is conducted and MSE are compare with existing estimators. The results show that proposed estimators are perform efficiently as compared to the existing estimators