Journal of Statistical Planning and Inference, Nov 30, 1989
The concept of model-robustness introduced by Wu (1981) is investigated for a class of designs re... more The concept of model-robustness introduced by Wu (1981) is investigated for a class of designs relative to a general optimality criterion, in the setup of Li (1983). A minimaxity result is established, which demonstrates that, for certain types of model inadequacies, randomization validates model based optimality results for many designs, including block designs and rowcolumn designs. The class of optimality criteria considered includes the A-and E-criteria, but not the D-criterion. A counter-example shows that randomization does not guarantee modelrobustness of the D-optimality property.
... (23) Wellman, MW; Adams, WW; Wolff, R. A,; Wiff, DR; Fratini, AV Macromolecules, this issue. ... more ... (23) Wellman, MW; Adams, WW; Wolff, R. A,; Wiff, DR; Fratini, AV Macromolecules, this issue. ... (33) Brant, DA; Miller, W. G.; Flory, PJ J. Mol. Bid. 1967,23, 47. (34) Welsh, WJ; Bhaumik, D.;Mark, JE Air Force Technical Report AFML-TR-78-3683. J. Macromol. ...
Confusions between drug names that look and sound alike are common, costly, harmful, and difficul... more Confusions between drug names that look and sound alike are common, costly, harmful, and difficult to prevent. One prevention strategy is to screen proposed new drug names for confusability before approving them. Widespread acceptance of pre-approval tests of confusability is compromised by the lack of experimental designs and statistical methods to support valid inferences about whether a proposed new name is unacceptably confusing. One way of identifying confusing names is to conduct memory and perception experiments on a set of drug names which would include both the new name and a set of control names (e.g., names already on the market). The experiment would yield an observed error rate for every name. Inferences about the acceptability of the new name can be made by comparing the error rate of the new name to the distribution of error rates of the control names. We describe four memory and perception experiments on drug names, carried out using clinicians as participants.
The role of atmospheric ozone to protect the living organism from the ul- traviolet radiation is ... more The role of atmospheric ozone to protect the living organism from the ul- traviolet radiation is well known. It saves the earth from the ultraviolet radiation emitted by the sun. Some stable chlorine gases released by the human activities going above the earth eat up the ozone layer. Depletion of the ozone layer is a great threat to the human society. In this paper, we discuss the lethal effects of the ozone depletion and compute the upper and lower β content confidence limits for an extreme value distribution and show that this can be used to calculate the upper and lower tolerance limits to the level of atmospheric ozone layer. The technique is explained by a data set.
In probability theory, central limit theorems (CLTs), broadly speaking, state that the distributi... more In probability theory, central limit theorems (CLTs), broadly speaking, state that the distribution of the sum of a sequence of random variables (r.v.'s), suitably normalized, converges to a normal distribution as their number n increases indefinitely. However, the preceding convergence in distribution holds only under certain conditions, depending on the underlying probabilistic nature of this sequence of r.v.'s. If some of the assumed conditions are violated, the convergence may or may not hold, or if it does, this convergence may be to a nonnormal distribution. We shall illustrate this via a few counter examples. While teaching CLTs at an advanced level, counter examples can serve as useful tools for explaining the true nature of these CLTs and the consequences when some of the assumptions made are violated.
Journal of Physics E: Scientific Instruments, 1988
... in Materials vol. I) (Oxford: Pergamon) Fadel MA, Abdalla A A and Hamid M A 1981 Degradation ... more ... in Materials vol. I) (Oxford: Pergamon) Fadel MA, Abdalla A A and Hamid M A 1981 Degradation of polycarbonates with fast neutrons and gamma rays and its application in radiation dosimetry Nucl. Instrum. Methods 187 505 ...
Introduction. Neurological diseases are very important causes of prolonged morbidity and disabili... more Introduction. Neurological diseases are very important causes of prolonged morbidity and disability leading to profound financial loss. Epilepsy is one of the most important neurological disorders. It being a cost intensive disorder poses a significant economic burden to the country. Aims and Objectives. The study was conducted among the persons with epilepsy (PWE) to assess their expenditure pattern for epilepsy treatment and its rural urban difference. Materials and Methods. 315 PWE selected by systematic random sampling and their caregivers were interviewed with the predesigned, pretested semistructured proforma. Subsequently data were compiled and analyzed using SPSS 18.0 software. Results and Conclusion. Majority of the study population were in the age group of 16-30 years. Majority belonged to classes IV and V of Prasad socioeconomic status scale. Average total expenditure per month for treatment of epilepsy was 219 INR, mainly contributed by drugs, travel, investigations, and so forth. Rural population was having higher treatment expenditure for epilepsy specially for travel and food and lodging in order to get epilepsy treatment. Wage loss in the last three months was present in 42.86% study subjects which was both affected by seizure episodes and travel for visits. Better district care would have helped in this situation.
SUMMARY. In a conventional functional linear model, incorporating a Bayesian experimental design,... more SUMMARY. In a conventional functional linear model, incorporating a Bayesian experimental design, universal optimality property is studied in the light of Schur-convexity. Construction of such universally optimal designs in a variety of useful models is presented in a unified manner.
SUMMARY. A competing effects model introduced by Raghavarao, Federer and Schwa- ger (1986) is con... more SUMMARY. A competing effects model introduced by Raghavarao, Federer and Schwa- ger (1986) is considered in the class of binary designs. It is shown that for estimating the competing effects and also for estimating the treatments and competing effects together, a 3-design is universally optimal.
Administration and policy in mental health, Jan 10, 2014
Optimal design has been an under-utilized methodology. However, it has significant real-world app... more Optimal design has been an under-utilized methodology. However, it has significant real-world applications, particularly in mixed methods implementation research. We review the concept and demonstrate how it can be used to assess the sensitivity of design decisions and balance competing needs. For observational studies, this methodology enables selection of the most informative study units. For experimental studies, it entails selecting and assigning study units to intervention conditions in the most informative manner. We blend optimal design methods with purposeful sampling to show how these two concepts balance competing needs when there are multiple study aims, a common situation in implementation research.
Journal of Statistical Planning and Inference, Nov 30, 1989
The concept of model-robustness introduced by Wu (1981) is investigated for a class of designs re... more The concept of model-robustness introduced by Wu (1981) is investigated for a class of designs relative to a general optimality criterion, in the setup of Li (1983). A minimaxity result is established, which demonstrates that, for certain types of model inadequacies, randomization validates model based optimality results for many designs, including block designs and rowcolumn designs. The class of optimality criteria considered includes the A-and E-criteria, but not the D-criterion. A counter-example shows that randomization does not guarantee modelrobustness of the D-optimality property.
... (23) Wellman, MW; Adams, WW; Wolff, R. A,; Wiff, DR; Fratini, AV Macromolecules, this issue. ... more ... (23) Wellman, MW; Adams, WW; Wolff, R. A,; Wiff, DR; Fratini, AV Macromolecules, this issue. ... (33) Brant, DA; Miller, W. G.; Flory, PJ J. Mol. Bid. 1967,23, 47. (34) Welsh, WJ; Bhaumik, D.;Mark, JE Air Force Technical Report AFML-TR-78-3683. J. Macromol. ...
Confusions between drug names that look and sound alike are common, costly, harmful, and difficul... more Confusions between drug names that look and sound alike are common, costly, harmful, and difficult to prevent. One prevention strategy is to screen proposed new drug names for confusability before approving them. Widespread acceptance of pre-approval tests of confusability is compromised by the lack of experimental designs and statistical methods to support valid inferences about whether a proposed new name is unacceptably confusing. One way of identifying confusing names is to conduct memory and perception experiments on a set of drug names which would include both the new name and a set of control names (e.g., names already on the market). The experiment would yield an observed error rate for every name. Inferences about the acceptability of the new name can be made by comparing the error rate of the new name to the distribution of error rates of the control names. We describe four memory and perception experiments on drug names, carried out using clinicians as participants.
The role of atmospheric ozone to protect the living organism from the ul- traviolet radiation is ... more The role of atmospheric ozone to protect the living organism from the ul- traviolet radiation is well known. It saves the earth from the ultraviolet radiation emitted by the sun. Some stable chlorine gases released by the human activities going above the earth eat up the ozone layer. Depletion of the ozone layer is a great threat to the human society. In this paper, we discuss the lethal effects of the ozone depletion and compute the upper and lower β content confidence limits for an extreme value distribution and show that this can be used to calculate the upper and lower tolerance limits to the level of atmospheric ozone layer. The technique is explained by a data set.
In probability theory, central limit theorems (CLTs), broadly speaking, state that the distributi... more In probability theory, central limit theorems (CLTs), broadly speaking, state that the distribution of the sum of a sequence of random variables (r.v.'s), suitably normalized, converges to a normal distribution as their number n increases indefinitely. However, the preceding convergence in distribution holds only under certain conditions, depending on the underlying probabilistic nature of this sequence of r.v.'s. If some of the assumed conditions are violated, the convergence may or may not hold, or if it does, this convergence may be to a nonnormal distribution. We shall illustrate this via a few counter examples. While teaching CLTs at an advanced level, counter examples can serve as useful tools for explaining the true nature of these CLTs and the consequences when some of the assumptions made are violated.
Journal of Physics E: Scientific Instruments, 1988
... in Materials vol. I) (Oxford: Pergamon) Fadel MA, Abdalla A A and Hamid M A 1981 Degradation ... more ... in Materials vol. I) (Oxford: Pergamon) Fadel MA, Abdalla A A and Hamid M A 1981 Degradation of polycarbonates with fast neutrons and gamma rays and its application in radiation dosimetry Nucl. Instrum. Methods 187 505 ...
Introduction. Neurological diseases are very important causes of prolonged morbidity and disabili... more Introduction. Neurological diseases are very important causes of prolonged morbidity and disability leading to profound financial loss. Epilepsy is one of the most important neurological disorders. It being a cost intensive disorder poses a significant economic burden to the country. Aims and Objectives. The study was conducted among the persons with epilepsy (PWE) to assess their expenditure pattern for epilepsy treatment and its rural urban difference. Materials and Methods. 315 PWE selected by systematic random sampling and their caregivers were interviewed with the predesigned, pretested semistructured proforma. Subsequently data were compiled and analyzed using SPSS 18.0 software. Results and Conclusion. Majority of the study population were in the age group of 16-30 years. Majority belonged to classes IV and V of Prasad socioeconomic status scale. Average total expenditure per month for treatment of epilepsy was 219 INR, mainly contributed by drugs, travel, investigations, and so forth. Rural population was having higher treatment expenditure for epilepsy specially for travel and food and lodging in order to get epilepsy treatment. Wage loss in the last three months was present in 42.86% study subjects which was both affected by seizure episodes and travel for visits. Better district care would have helped in this situation.
SUMMARY. In a conventional functional linear model, incorporating a Bayesian experimental design,... more SUMMARY. In a conventional functional linear model, incorporating a Bayesian experimental design, universal optimality property is studied in the light of Schur-convexity. Construction of such universally optimal designs in a variety of useful models is presented in a unified manner.
SUMMARY. A competing effects model introduced by Raghavarao, Federer and Schwa- ger (1986) is con... more SUMMARY. A competing effects model introduced by Raghavarao, Federer and Schwa- ger (1986) is considered in the class of binary designs. It is shown that for estimating the competing effects and also for estimating the treatments and competing effects together, a 3-design is universally optimal.
Administration and policy in mental health, Jan 10, 2014
Optimal design has been an under-utilized methodology. However, it has significant real-world app... more Optimal design has been an under-utilized methodology. However, it has significant real-world applications, particularly in mixed methods implementation research. We review the concept and demonstrate how it can be used to assess the sensitivity of design decisions and balance competing needs. For observational studies, this methodology enables selection of the most informative study units. For experimental studies, it entails selecting and assigning study units to intervention conditions in the most informative manner. We blend optimal design methods with purposeful sampling to show how these two concepts balance competing needs when there are multiple study aims, a common situation in implementation research.
Uploads
Papers by Dulal Bhaumik