Sample Statistics - Two Variables Flashcards
1
Q
how can we quantify the relationship between two variables
A
covariance and correlation
2
Q
when does the covariance =0
A
when the two variables are independent
3
Q
what is a drawback of the covariance
A
depends on the spread of the data and the scale used to measure them
4
Q
what is pearson’s correlation coefficient - r
A
the covariance divided by the product of the standard deviations of the two variables
5
Q
if r is close to 1
A
data points almost lie on a line of positive slope
6
Q
if r is close to 0
A
data points are randomly scattered
7
Q
if r is close to -1
A
data points almost lie on a line of negative slope
8
Q
how do you estimate the intercept (alpha) and the slope of a best fitting line
A
least squares best fit method
