Module 12 Notes Intro Day 2
We want lines of the form: y
= b + mx
We can also use descriptive statistics from Statcrunch to calculate slope and y intercept.
What do each of the variables mean?
mr
sy
sx
b  y  mx
s y : is standard deviation of all the y values which measures the variability of the y coordinates
s x : is standard deviation of all the x values which measures the variability of the x coordinates
The r value will place the negative or positive sign on the slope.
To find b, the y-intercept, we need a point to plug into y = b + mx. The point that is chosen is ( x , y ) which
represents the mean y value and mean x value.
Using the following computer generated statistics, we can find the least squares regression line.
Computer technology can give us the equation directly as well.
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