Tag Archives: Chi-Square Test

Comparison of Two or More Correlated AUCS in Paired Sample Design (Published)

The performance of a diagnostic test when test results are measured on a binary or ordinal scale can be evaluated using the measures of sensitivity and specificity. In particular, when it is measured on a continuous scale, the assessment of the performance of a diagnostic test is always over the range of possible cut-off points for the predictor variable. This is achieved by the use of a receiver operating characteristic (ROC) curve which is a graph of sensitivity against 1-specificity across all possible decision cut-offs values from a diagnostic test result. This curve evaluates the diagnostic ability of tests to discriminate the true state of subjects and compare the performance of two alternative diagnostic tests performed on the same subject. These tasks of comparing diagnostic tests is always better achieved using a summary measure of accuracy across all possible ranges of cut-off values called the area under the receiver operating characteristic curve (AUC).So many parametric and nonparametric methods exist for comparing two or more correlated AUCs in diagnostic tests when the data is paired. In this paper, we proposed a simple and easy to understand chi-square method of comparing two or more AUCs in a paired sample design. The proposed method which does not require the knowledge of true status of subjects or gold standard in evaluating the accuracy of tests unlike the existing methods, it offers reliable statistical inferences even in small sample problems and circumvent the difficulties of deriving the statistical moments of complex summary statistics as seen in the Delong et al method. The proposed method provides for further analysis to determine the possible reason for rejecting the null hypothesis of equality of AUCs. The proposed method when applied on real data, was shown to be better than the Delong et al method as it avoids the lengthy and more difficult procedures of estimating the variances of two AUCs as a way of determining if two AUCs differ significantly. The method is validated using the Cochran Q test and was shown to compare favourably.  

Keywords: AUC, Chi-Square Test, Cochran Q Test, Cut-Off Value, Delong et al, Dichotomous Data, Predicted Probability, ROC

Use of Digital Storytelling as a Teaching Tool at National University of Science and Technology (Review Completed - Accepted)

Digital Storytelling is a very popular teaching and learning technique used worldwide today. This teaching methodology has equally been used at universities and schools throughout different regions and cultures for the common aim to enhance the learning experience of students. Hence various studies have been conducted to estimate the extent of usage and effectiveness of this technique by both faculty members and students. The previously conducted studies are characterized over varying response variables, sample size, sample characteristics etc but all these studies converged the common results of enhanced learning experience among the students. Additionally the studies also exhibited the educational and instructive knowledge and the openness towards the adoption of new teaching methods by the faculty members. Our study conducted at National University of Science and Technology, based over a sample size of 100 respondents divided equally among students and faculty, investigates the use of DST tools by the faculty and its effectiveness on student learning shows a positive relationship between the departments of faculty and students’ learning.

Keywords: Chi-Square Test, Digital Story Telling

Use of Digital Storytelling as a Teaching Tool at National University of Science and Technology (Review Completed - Accepted)

Digital Storytelling is a very popular teaching and learning technique used worldwide today. This teaching methodology has equally been used at universities and schools throughout different regions and cultures for the common aim to enhance the learning experience of students. Hence various studies have been conducted to estimate the extent of usage and effectiveness of this technique by both faculty members and students. The previously conducted studies are characterized over varying response variables, sample size, sample characteristics etc but all these studies converged the common results of enhanced learning experience among the students. Additionally the studies also exhibited the educational and instructive knowledge and the openness towards the adoption of new teaching methods by the faculty members. Our study conducted at National University of Science and Technology, based over a sample size of 100 respondents divided equally among students and faculty, investigates the use of DST tools by the faculty and its effectiveness on student learning shows a positive relationship between the departments of faculty and students’ learning.

Keywords: Chi-Square Test, Digital Story Telling