THE COMPARISON OF THE ORDINAL LOGISTIC MODEL WITH THE CLASSICAL REGRESSION MODEL
Nurul Astuty Yensy
Bengkulu University
Abstract
This research-s aims was to provide an alternative for observer and statistical user who were interested in analyzing the functional relationship between ordinal response variable and explanatory variable. The data used was the data of Students on Generation 2017 JPMIPA FKIP Bengkulu University. The data required was a student-s GPA for two semesters (semester I and II), that was as a response variable with 5 categories of grade (GPA < 2.0 worth 1; 2.0 ≤ GPA < 2.5 worth 2; 2.5 ≤ GPA < 3.0 worth 3; 3.0 ≤ GPA <3.5 value 4 and GPA ≥ 3.5 value 5). While the free variables included: Gender, Fathers Education, Fathers Occupation, Parents Income, Mothers Education, Mothers Occupation, High School Status, Average of High School Report, National Examination, UNIB admission pathway and suitability of study program. The test statistic from the modified probability ratio in ordinal logistic had a higher test power than the F test in the classical linear regression for H0: β = 0. Overall the probability of rejection (H0: β = 0) of ordinal logistic tended to be lower than the classical regression . At condition of ρ close to 1, the test power of the ordinal logistic would be the same as the classical regression. Ordinal logistic model tended to be more selective in choosing variables that significantly affect the response, resulting in a simpler model than the classical regression. The results of the research with the classical linear model (significant level α = 0.05) obtained variables that influence the student GPA were UN score, High School Report, UNIB admission pathway, High School Status and interaction of UN Score & High School Status. While the ordinal logistic model produced influential independent variables were the UN Score, High School Report, High School Status and the interaction of UN Score & High School Status.
Keywords: Ordinal Logistic, Classical Regression, Categorical Variable, Power of Test
Topic: Mathematics