dumb stats question i am embarrassed about the basicness of it so im hiding it in thread below, but i would like help understanding
20
6
105
Conversation
i think i know roughly how correlations work - if u plot the values, u can get a trendline (the line that minimizes distance from line to all the points). if u then take this line and calculate square root of distance from line to points... something something correlation
3
29
like, if all the points are real far from the line, its low correlation, if all the points are close to the line, its high correlation
but i don't understand the relationship of this to the slope of the line itself?
13
19
like what does it *mean* for there to be a real strong trend slope with an r of 0.02? Or weak with r of .9? is that even possible? what does this even mean about the data?
i conceive of correlations as about predictive power - given knowledge of X, how can we predict Y?
15
1
17
Replying to
By “strong trend slope” here are you meaning literally the “steepness”? Like you’re wondering how can you get really big coefficients with low correlation and vice versa?
1
I think technically correlation just means the relationship between your data, while the coefficient just measures the linear correlation
No. In a univariate regression, the coefficient is the covariance of x and y divided by the variance of x (cov(x,y)/var(x)). Correlation is the covariance of x and y divided by the product of the standard deviation of x and the standard deviation of y.
2