Well, seems to be (Quotes from the Bible of Excel):
Calculates, or predicts, a future value by using existing values. The predicted value is a y-value for a
given x-value. The known values are existing x-values and y-values, and the new value is predicted by
using linear regression. You can use this function to predict future sales, inventory requirements, or
consumer trends. "
Calculates the point at which a line will intersect the y-axis by using existing x-values and y-values. The
intercept point is based on a best-fit regression line plotted through the known x-values and known yvalues.
Use the intercept when you want to determine the value of the dependent variable when the
independent variable is 0 (zero). For example, you can use the INTERCEPT function to predict a metal’s
electrical resistance at 0°C when your data points were taken at room temperature and higher."
In regression analysis, calculates an exponential curve that fits your data and returns an array of values
that describes the curve. Because this function returns an array of values, it must be entered as an array
Are the most common Formulas used
Most of the Available tools for Regression analysis are pay for items...
this link has a precis that claims to have the regression analysis explained, but I don't know since I can't comprehend the article