عنوان مقاله [English]
Climatic phenomena are complex. The complexity is that the phenomenon has many causes. The interrelationships between climatic elements and factors have led to the application of statistical methods, including multivariate statistical methods in climatic studies. One of these applications is to study and predict the relationship between climatic elements and factors. Application of statistical methods facilitates these studies. In this study, the relationship between the annual relative humidity and annual temperature with the number of annual days of precipitation of Zanjan station during the statistical period of 1956-2005 have been investigated. For this purpose, Pearson correlation methods have been used. Correlation means the covariance of two variables. The results show that the correlation coefficients of the variables are significant. furthermore, simple linear regression is used to estimate the number of annual days of precipitation with respect to annual relative humidity. Two-variable regression will be used to estimate the number of annual days of precipitation with respect to annual relative humidity and annual temperature.