hi,
That is the formula, usually Y = ax +b where a is the slope and b is the y
intercept.
In Excel you can use the =LINEST function to calculate various regression
parameters, you can use the TREND function to esimate a new y value based on
a given X. You can use the SLOPE function to find the slope of the linear
regression line for a series of point pairs, you can use the INTERCEPT
function to find the intercept of the same series. You can plot the data in
a chart and then ask Excel to plot a Linear trendline and display the formula
on the chart. Or you can use the Data Analysis command's Regression tool to
present a myrid of regression statisticsl.