Abstract: This study is concerned with the study of the degree of relationship between BMI, age and sex and the estimation of the survival function of Kumaraswam distribution with two parameters by four methods of estimation: MLE, moment, order maximum and Linear moments to determine the effect of obesity on probability of survival by calculating the probabilistic survival values of each BMI value and by experimental study using simulation and by observations generated from the Kumaraswam distribution and for sample sizes 40 and 100, the four methods were linear moments was more efficiency based on statistical standards Akaike AIC, Standard Error (SE) and CV.