line of best fit: the points within the one line

correlation of the data

independent and dependent variableindependent variable: x axis written - which we want to predict (which we cannot control)dependent variable: y-axis written - which we varies because of independent variable

strength of association between two variables, X and Y.This is -1 to +1.perfectly linear when r=1Positive correlation means r>0

Negative correlation means r<0Zero correlation means r=0

Positive and Negative Correlations

Positive means the variables depend on each other in a way that if one increases then the other increases.

Negative means the variables depend on each other but when one variable increases then the other decreases.

limitation: it does not tell you why the correlation is stated in that value.

remember Sxx and Syy cannot be negative. Well Sxy may be or can be negative or positive though

Line of regression

This is to get the minimized vertical distances between the lines and points.

How to solve line of regression?

If calculating regression of data, then we square coefficient value.For example, if r is 0.8 then regression would only be 0.64. This means to say that it is not as worthy as it used to look like when it was coefficient value.