PARAMETERS

This research will undertake a comprehensive statistical analysis of Nigeria's
Exchange rate spanning a decade, with a focus on estimating Autoregressive (AR) models using a prominent statistical methods: the Yule-Walker method. The study aims to provide statistical insights into the underlying dynamics of Nigeria's economic performance during this period. The research will commence by delineating the statistical framework of AR models, which offer a statistical representation of a time series based on its past values. Subsequently, the Yule-Walker method will be introduced, a statistical technique leveraging autocorrelation functions to estimate AR model parameters. The statistical properties of Yule-Walker estimators will be elucidated in the context of Nigeria's Exchange rate data. In contrast, the Least Squares method will be presented as an alternative statistical approach, characterized by its objective to minimize the sum of squared prediction errors. A statistical framework for the least squares estimators will be outlined, providing insights into the statistical properties of parameter estimates and their significance in explaining variations in Nigeria's Exchange rate. The core of the research involves the statistical analysis of Nigeria's Exchange rate time series data over the forty-three year period. The Yule-Walker method will be applied to estimate AR models tailored to the Exchange rate data. The statistical comparison will be based on goodness-of-fit statistics, such as the Akaike Information Criterion (AIC), to evaluate the models' adequacy in capturing the statistical patterns within the Exchange rate dataset.

Aspartame (ASP) is an artificial sweetener used in food products as an alternative to sugar. Concerns relating to the possible adverse health effects of its consumption have been raised due to aspartame’s metabolic components which are formed during its breakdown. Some research studies have associated aspartame consumption with health disorders such as cancers, neurochemical changes, hepatotoxicity etc, since the liver helps in the metabolism and detoxification of harmful substances and drugs, it acts as a filter to clean the blood. Therefore, the purpose of this study was to investigate the effect of aspartame on liver function parameters in male Sprague Dawley rats. The rats were thirty-one (31) and were divided into five (5) groups: control, groups B-E. Group A (control) received 0.5ml of plain distilled water via gastric gavage. Group B, Group C, Group D, and Group E received (40, 80, 160, 320) mg/kg respectively for a duration of 75days. Results from this study showed a dose-dependent increase in serum Alkaline Transaminase (ALT) concentration between the control and the groups administered aspartame, but the liver ALT showed no significant difference. However, there was no significant difference between the means of the serum Aspartate Transaminase (AST) of the control group and groups administered aspartame. Also the result shows a dose dependent decrease in serum Alkaline Phosphatase (ALP), and a non significant difference in the means of liver ALP. Result from the present study showed significant difference in serum Gammaglutamyl Transferase (GGT) only when the control group was compared with the group administered 40mg/kg. However, the serum protein, heart protein and liver protein results between all groups in this study, showed no significant difference, but however a significant decrease was observed in the kidney proteins of the rats administered aspartame, especially in the group that received 160mg/kg. The level of testis protein increased in the groups that received 80mg/kg and 160mg/kg when compared to control. However, the amount of serum globulin in the aspartame-administered groups was not different from that of the control group. Aspartame may act as a chemical stressor by altering organ function homeostasis and increasing protein oxidative damage. This might play a significant role in promoting apoptotic cell death leading to damage of the organs and subsequently death.