![]() So the mean is three,Īnd this is one sample standard deviation for y above the mean and this is one standardĭeviation for y below the mean. We could do the same thing for the y variables. Sample standard deviation below the mean, and then Sample standard deviation above the mean, this is one Is eight divided by four, which is two, so we have xĮquals two right over here. One plus two plus two plus three divided by four, Here, so the sample mean for x, it's easy to calculate In red so that you know that's what is going on Sample standard deviation for x are here in red, and actually let me box these off We clearly have the fourĭata points plotted, but let's plot the statistics for x. So before I do that, let's just visualize some of the statistics that we have here for these data points. On this video is build on this notion and actuallyĬome up with the equation for the least squares We got an r of 0.946, which means we have a fairly If r is equal to zero, you don't have a correlation, but for this particular bivariate dataset, One, you have a perfect negative correlation, and And as we said, if r is equal to one, you have a perfect positive correlation. The product of the z scores for each of those pairs. In that video we saw all it is is an average of In previous videos, we took this bivariate data and weĬalculated the correlation coefficient, and justĪs a bit of a review, we have the formula here, and it looks a bit intimidating, but This has applications in machine learning and AI - FYI. Wouldn't have thought about it and was going to skip this video. ![]() So we substitute the m, Xmean, Ymean, and then get Y intercept. We know for a fact that for the regression line function, we have Xmean and Ymean as part of its points or at its intersection. But the r also factors into this calculation. Then he shows that rise over run, which is slope, is equal to Sy/Sx. And then he draws 1 stddev lines for x and y axis. They have also provided x,y mean and stddev.įirst they use the Xmean and Ymean as reference. He shows formula to get the correlation coefficient, but they have already done all the calculation to get the best correlation coefficient. Goal is to find regression line that best fits the data point. ![]()
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