摘要：Dear Editor in Chief: Central and dispersion indices of statistical distri-bution of a random phenomenon together show the behavior pattern of that phenomenon. In healthcare researches, researchers are mainly inter-ested in examining the impact of various factors on the behavior of a random phenomenon. One of the useful tools to achieve this goal is the use of statistical models such as linear regression model. Linear regression model estimates effect of differ-ent factors on the mean of a quantitative response variable, which is the variable that we examine effect of other factors on it.
