Correlation Flashcards
Positive correlation
as x increases, so does y
negative correlation
as x increases, y decreases
correlation coefficient
r
what is correlation
how well the points in a graph suggest a pattern
r = 0
no correlation between x and y
r = 1
perfect positive correlation
- as r gets closer to 1 the more perfect the correlation is
r = -1
perfect negative correlation
- as r gets closer to -1 the more perfect the correlation gets
line of best fit
used to make predictions
aka regression line
extrapolation vs interpolation
if the line of best fit is used to make a prediction, and y is in the boundaries of the data than it is reliable. and is called interpolation
if y is outside of the data, then this is not reliable and is called extrapolation
how to find y from x
use line of best fit
how to find x from y
not possible
mean
always contained in the line of best fit
calculator to find line of best fit
go to stat, enter data
go back to stat, go to 4
press calculate
r = correlation
a = x
b = y
how to graph a line from a scatter plot
find the gradient from two points
then use one point as x and y to find c
gradient
the amount of ____ that declines/increases in relation to ____
(changine in y/change in x)
