The research is concerned with the development of a mathematical model for estimating Intelligent Quotient of human above 65years. The model was optimized to know whether we have maximum or minimum human IQ level. However, the optimization result showed a saddled point which indicates that there is no minimum or maximum human IQ in life. This result implies that there is no particular IQ level that any human above 65years cannot attain when there is an enabling environment for adult education and other adult related trainings geared towards sharpening IQ skills of our retired and aged people. Similarly the IQ model was also validated with data from real life. And the outcome of the validation gave a correlation coefficient of 0.990405. This implies that our model is approximately 99% in agreement with real life data used, thus shows that the model is a standard measure for estimating IQ of human above 65years.

The research is concerned with the development of a mathematical model for predicting the rate of human happiness and to outline factors that influence human happiness. The model was optimized and observation about the model’s extreme value was made. The outcome of the optimization result showed that happiness has neither minimum nor maximum level that should be required in human. It means someone’s happiness could be close to 0% or even be up to 100%. Thereafter, the model was analysed and the collated real-life data were correlated with those of the model data (H model) using suitable statistical tools. The findings from the correlation result showed that the questionnaire result attained a 70% degree of correlation with the estimated model result (H model), and thus recommending the model as a standard measure for predicting the rate of human happiness.

Given that divorce has become a recurring challenge with increasing intensity in our world today accompanying broken families, economy and social contagion, as well as the existence of difference in happiness between the couple and their children. Thus, a mathematical model for predicting the rate of divorce tendencies in the Nigerian society is hereby developed. Factors influencing the rate of divorce were outlined and mathematical relationships between these factors were established. Afterwards, the developed model was validated and the real life data collected were contrasted with the model data predictions using suitable statistical tools. The findings from the comparison showed that the real life data and the model data predictions have a higher degree of correlation; consequently, recommending the model as a benchmark measure for predicting rate of divorce/marital instability in Nigeria. In the same vein, recommendations were made at the end of the model analysis which when adhered to would yield.