Two-Way Contingency Table Analysis for Casualty Due to Road Traffic Crashes

Abstract

Road traffic crash is an event on the road that is wished never to occur. Much more scared and worrisome is casualty due to road traffic crash. As a nation it is important to know where casualty due to road traffic crash occurs the most for appropriate interventions. This study aimed at investigating whether there is significant relationship between geo political regions in Nigeria and outcome of road traffic crash, where the target outcome is the casualty due to road traffic crashes. Data on number of casualties and non-casualties for each geopolitical region of Nigeria from the year 2016 to 2022 was collected and presented in a 6×2 contingency table. Pearson Chi Square test and Likelihood Ratio Chi Square test for independence were used to determine whether there is relationship between the geopolitical region and outcome of road traffic crash. Result revealed that there is significant relationship between the two categorical variables. To determine significant associations in the 6×2 contingency table, 15 possible local 2×2 tables were derived from the 6×2 contingency table, and odds ratio as a measure of association was employed. Results revealed that significantly, the odds ratio for each of the 15 possible local 2×2 tables are not equal to 1. Conclusively, the geopolitical region with the least casualties due to road traffic crashes in Nigeria is South East. Higher than South East region is South South region. Higher than South South region is South West Region. Higher than South West region is North West region. Higher than North West region is North East Region. The geopolitical region with the greatest casualties due to road traffic crash in Nigeria is North Central. Generally, the Northern region of Nigeria suffered higher casualties than the Southern region. More attention needs be given to stop the higher casualties suffered in the Northern region of Nigeria and particularly, in the North Central region.