Calculating the Y-Intercept

How to Subscribe
MLS & MLT Comprehensive CE Package
Includes 176 CE courses, most popular
$109Add to cart
Pick Your Courses
Up to 8 CE hours
$55Add to cart
Individual course$25Add to cart
Need multiple seats for your university or lab? Get a quote
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)
Calculating the Y-Intercept

To find the y-intercept, calculate and , the average of the x- and y-values respectively.


Then substitute these two values for x and y in the = b + a equation. Finally, solve for the unknown quantity a. Remember from the previous page that:
b = 0.002 = slope
0.35 = a + 0.002(175)
0.35 = a + 0.35
0 = a
Therefore, the complete relationship between glucose concentration and absorbance for the data is y = 0+ 0.002x, or y = 0.002x, where y is the absorbance and x is the glucose concentration.