The page below is a sample from the LabCE course Linear Regression Analysis. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Linear Regression Analysis (online CE course) »
How to Subscribe
MLS & MLT Comprehensive CE Package
Includes 97 CE courses, most popular
$95 Add to cart
Pick Your Courses
Up to 8 CE hours
$50 Add to cart
Individual course$20 Add to cart

Formulae for Determining the Slope and Intercept

To find the slope, calculate the deviation of each x from mean, , and calculate the deviation of each y from its mean, . The numerator is the product of the deviation of each x and y pair, the denominator is the sum of the squared deviations of all of the x-values. Thus the formula is:

The y-intercept, a, is calculated by substituting and into the equation of a line and solving for a:

To draw this line on a graph, substitute two or three values for x, calculate the corresponding y values, plot these x-y pairs as points on the graph, and draw a line through these points.