Related Function:
The INTERCEPT function calculates the point at which a line will intersect the yaxis by using existing xvalues and yvalues.
Syntax
=INTERCEPT(known_y’s,known_x’s)
Arguments
Argument  Description 

known_y’s  The dependent set of observations or data 
known_x’s  The independent set of observations or data 
Note: The length of the known_x’s array should be the same length as known_y’s array, and the variance of the known_x’s must not be zero.
Examples
A  B  C  D  

1  Known Xs  Known Ys  
2  12  15  
3  17  18  
4  14  27  
5  13  16  
6  5  28  
7  
8  Formula  Result  Notes  
9  =INTERCEPT(B2:B6,A2:A6)  29.59391  Point at which a line will intersect the yaxis by using the xvalues and yvalues above 
Common Function Error(s)
Problem  What went wrong  

#N/A  Occurs if the supplied known_x’s and known_y’s arrays are of different lengths  
#DIV/0!  Occurs if either:

The slope function uses the following equation to calculate the intercept of the linear regression line, a:
where the slope, b, is calculated as:
and the values of x and y are the samples means (averages) of the known_x’s and the known_y’s.
See Wikipedia for more information on linear regression.