Thank you for the opportunity to help you with your question!
This is what she does to come up withe the regression line:
She first calculates the following
The mean of the x values
The mean of the y values
The standard deviation of the x values (denoted sx)
The standard deviation of the y values (denoted sy)
The correlation between X and Y (denoted r)
The formula for the slope, m, of the best-fitting line is
where r is the correlation between X and Y, and sx and sy are the standard deviations of the x-values and the y-values, respectively. You simply divide syby sx and multiply the result by r.
She then finds the y intercept using the formula below
are the means of the x-values and the y-values, respectively, and m is the slope.
So to calculate the y-intercept, b, of the best-fitting line, you start by finding the slope, m, of the best-fitting line using the above steps. Then to find the y-intercept, you multiply m by
For more information get a step by step guide for dummies
Please let me know if you need any clarification. I'm always happy to answer your questions.
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