Department of Statistics: Recent submissions

Now showing items 61-80 of 103

The development of a goodness-of-fit test for high level binary multilevel models.

Fernando, G.; Sooriyarachchi, M.R. (Taylor and Francis, 2020)

Before making inferences about a population using a fitted model, it is necessary to determine whether the fitted model describes the data well. A poorly fitted model may lead to biased and invalid conclusions, resulting ...
Comparison of methods for analyzing binary repeated measures data: A simulation-based study comparison of methods for binary repeated measures

Gawarammana, M. B. M. B. K.; Sooriyarachchi, M.R. (Taylor and Francis, 2017)

Binary Repeated Measures (BRM), Weighted Least Squares (WLS), Generalized Estimating Equation (GEE), Generalized Linear Mixed Models (GLMMs), Simulation Study, SAS
A goodness of fit test for multilevel survival data

Balakrishnan, K.; Sooriyarachchi, M.R. (Taylor and Francis, 2018)

No satisfactory goodness of fit test is available for multilevel survival data which occur when survival data are clustered or hierarchical in nature. Hence the aim of this research is to develop a new goodness of fit ...
A study of the effect of water quality related variables on some age related diseases adjusted for other well-known risk factors: a multivariate multilevel study

Ranatunge, K.N.O.; Sooriyarachchi, M.R. (IWA Publishing, 2017)

Mortality rates of some diseases are affected by water quality. This research examines the roles of two factors related to water quality, namely the quality of drinking water termed ‘water’ and the quality of sanitation ...
Simulation study of a novel method for comparing more than two independent receiver operating characteristic (ROC) curves based on the area under the curves (AUCs).

Meyen, A.N.; Sooriyarachchi, M.R. (National Science Foundation, Sri Lanka, 2015)

Receiver operating characteristic (ROC) graphs are useful for organising binary classifiers and visualising their performance. In order to compare classifiers it may be needed to reduce the ROC performance to a single ...
) A multilevel Bayesian analysis of university entrance eligibility for selected districts in Sri Lanka: Methods and Application to educational data

Jayawardene, N.I.; Sooriyarachchi, M.R. (National Science Foundation, Sri Lanka, 2014)

Multilevel data structures are becoming a commonly encountered phenomenon in educational research. This type of data generates a number of statistical problems, of which clustering is particularly important. To solve ...
The use of mid-trial reviews for design modifications in small scale clinical studies

Sooriyarachchi, M.R.; Jayatillake, R.V.; Ranganath, H.; Eddleston, M. (Elsevier, 2010)

Many clinical studies such as those in the areas of toxicology, early phase clinical trials and bioequivalence studies use small samples due to the high cost of experimentation. These studies test hypotheses based on ...
Guidelines for calculating sample size in 2x2 Crossover Trials : A simulation study

Siyasinghe, N.; Sooriyarachchi, M.R. (National Science Foundation, Sri Lanka, 2011)

In crossover trials, patients receive two or more treatments in a random order in different periods. The sample size determination is often an important step in planning a crossover study. This paper concerns sample ...
Adjusting for a cluster effect in the Logistic Regression Model : An illustration of theory and its application.

Jayatilleke, R.V.; Sooriyarachchi, M.R.; Senerathna, D.L.P. (National Science Foundation, Sri Lanka, 2011)

When a response having two outcomes is modelled using a logistic model the responses on each observation are often considered to be independent of each other. This assumption may not always be valid and the responses ...
Generalized Cochran Mantel Haenszel test for multilevel correlated categorical data: an algorithm and R function

De Silva, DBUS; Sooriyarachchi, M.R. (National Science Foundation, Sri Lanka, 2012)

Multilevel data are a commonly encountered phenomenon in many data structures. Modelling such data requires careful consideration of the association between underlying variables at each level of the data structure. ...
Determining the Sensitivity and Specificity of a Substitute Test as a Diagnostic for its Gold Standard in the presence of Severe Missingness.

Senerathne, D.M.; Sooriyarachchi, M.R. (National Science Foundation, Sri Lanka, 2012)

When the need arises to identify a disease, substitute tests or screening tests are commonly used to recommend patients for its respective “Gold Standard”. Since it is seldom that these gold standards are carried out ...
A simulation based study for comparing tests associated with Receiver Operating Characteristic (ROC) curve

Jayasekera, D.; Sooriyarachchi, M.R. (Taylor and Francis, 2014)

Receiver Operating Characteristic curves and the Area Under Curve (AUC) are widely 7 used to evaluate the predictive accuracy of diagnostic tests. The parametric methods of 8 estimating AUCs are well established while ...
A Goodness of fit test for the Multilevel logistic model

Perera, Piumi; Sooriyarachchi, M.R.; Wickremasuriya, Shanika (Taylor and Francis, 2016)

It is crucial to test the goodness of fit of a model before it is used to make statistical inferences. However, no satisfactory goodness of fit test is available for the case of categorical multilevel data which occur when ...
Airline Seats Allocation Optimization Through Revenue Management

Saubhagya, K S; Wijesekara, W M L K N; Jayamanne, Imali T (Sri Lankan Journal of Applied Statistics, 2018)

Revenue Management has recently gained a solid recognition in Airline industry. It acts as a strategic and tactic provider to manage the uncertainty in demand for their perishable products in the most profitable manner as ...
Gender, Employment and Higher Education Theme: Trends in Employment Characteristics of Arts Graduates by Gender

Jayamanne, Imali T; Ramanayake, K. P. Asoka (VISTAS Journal, 2019)

At present, female enrollment for higher education is steadily increasing and contemporary it is about 80% for Arts discipline. An analogy to this, female labour force participation is also grown enormously. There may be ...
Employability and Related Context Prediction Framework for University Graduands: A Machine Learning Approach

Wijayapala, Manushi Prabhavi; Premaratne, Lalith; Jayamanne, Imali T (International Journalon Advances in ICT for Emerging Regions, 2016)

In Sri Lanka (SL), graduands’ employability remains a national issue due to the increasing number of graduates produced by higher education institutions each year. Thus, predicting the employability of university graduands ...
A Study on the Waiting Time for the First Employment of Arts Graduates in Sri Lanka

Jayamanne, Imali T; Ramanayake, K. P. Asoka (International Journal of Computer and Information Engineering, 2017)

Transition from tertiary level education to employment is one of the challenges that many fresh university graduates face after graduation. The transition period or the waiting time to obtain the first employment varies ...
Variance Corrected Proportional Hazard Model for the Analysis of Recurrent Multiple Failure Modes.

Amarasingh, N. S.; Sunethra, A.A.; Sooriyarachchi, M.R. (2013)

Automobiles do fail repetitively owing to different types of failures. Modeling of such products should concern dissimilar recurrent failure types. Failure types are habitually correlated to each other. This study has ...
Use of Sandwich Variance Estimation in Generalized Linear Mixed Models: for Binary Repeated Mesures Data

Sunethra, A. A.; Sooriyarachchi, M.R. (2016)

Sandwich Variance Estimation (SVE) is a method of estimating variances of miss-specified models and has been popular for analyzing correlated/non-independent data to improve the variance estimation of models fitted for ...
Variance-Corrected Proportional Hazard Models for the Analysis of Multiple Failures in Personal Computers

Sunethra, A. A.; Sooriyarachchi, M.R. (Wiley InterScience, 2011)

Proportional hazard (PH) modeling is widely used in several areas of study to estimate the effect of covariates on event timing. In this paper, this model is explored for the analysis of multiple occurrences of hardware ...

Now showing items 61-80 of 103

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