In a Simple Linear Regression Problem,the Following Statistics Are Calculated $$\sum ( x - \bar { x } ) ( y - \bar { y } ) = 2250 , s _ { x } = 10 , \sum x = 50 , \sum y = 75$$

In a simple linear regression problem,the following statistics are calculated from a sample of 10 observations: $$\sum ( x - \bar { x } ) ( y - \bar { y } ) = 2250 , s _ { x } = 10 , \sum x = 50 , \sum y = 75$$ .The least squares estimates of the slope and y-intercept are,respectively,

A) 1.5 and 0.5
B) 2.5 and 1.5
C) 1.5 and 2.5
D) 2.5 and -5.0