POPULATION

This study evaluated and compared the performance of three statistical methods for hypothesis testing when comparing means between two populations: the t-test, Welch's t-test, and the z-test. The t-test assumes normally distributed data and equal variances, while Welch's t-test accounts for unequal variances, and the nonparametric Mann- Whitney U test is an alternative for non-normal data. The research aimed to determine the optimal test by formulating hypotheses, selecting appropriate test statistics, determining sample sizes, and implementing the tests using R programming. The data analyzed were the mean heights of NBA guards and forwards during the 2022-2023 season. A power analysis assessed the reliability, validity, and assumptions of the tests. The results indicated a significant difference in mean heights between guards and forwards, with guards being slightly taller on average. Importantly, the Welch's t-test consistently outperformed the standard t-test and z-test across varying sample sizes, demonstrating higher power and a greater ability to detect true effects while minimizing Type I and Type II errors. This superior performance is attributed to the robustness of Welch's t-test in handling unequal variances between groups, a common scenario in real -world data analysis.

This research study was carried out to determine the impact of population growth on Nigerian Economy. The specific objectives of the study include investigating the relationship and effect of population growth on economic growth in Nigeria. This research study investigated the impact of population growth on the Nigerian economy using annual time series data for the period 1981 to 2024. The data was extracted from CBN statistical publications (2024), National Bureau of Statistics (2024). ADF technique in testing the unit root property of the series was utilized, the ARDL estimation technique was used to analyze the data. The research findings indicate the following: One year lag coefficient of Real Gross Domestic Product has a positive impact on the current value of Real Gross Domestic Product. Population growth has a positive impact on the current value of Real Gross Domestic Product. Poverty Head Count Ratio has a positive relationship with the current value of Real Gross Domestic Product. Unemployment rate has a positive relationship with the current value of Real Gross Domestic Product. Inflation rate has a positive impact on the current value of Real Gross Domestic Product. The prices of goods and services increases the value for goods and services also increase which eventually cause increase in the value of Real Gross Domestic Product