Correlation Flashcards
What is correlation?
Quantification of the degree of a relationship in deviations from the mean
What is Pearson’s correlation coefficient?
(r) strength of how X and Y are related
Range of Pearson’s Correlations Coefficient (r) is
[ -1
-1 : Perfect negative Correlation
0 : no correlation between variables
+1 : No correlation between variables
What would most likely the Range of (r) would be?
Decimal
What is the equation for solving (r)?
(r) =____ (x- xmean)(y-ymean) +….. etc.____
sqrt [(x-xmean)^2 +(x-xmean)^2] [(y-ymean)^2+(y-ymean)^2]
Basically what is a Correlation Coefficient?
Strength of a relationship
What matters when solving the Correlation Coefficient (r)?
N = Number of x variables
If you know “N” and “r” , what can it help solve?
P-value
Does a horizontal line and vertical line of correlation?
No
Correlation is NOT Causation. What does this mean?
Just because a variables is related to another, it DOES NOT mean changes in one variable will cause changes in the other
What happens to (r), if N is small?
(r) happens by chance
How do you find Degrees of Freedom when provided only N pairs?
Df= N pairs - 2
How do you find p-value in an r table?
Find the Degrees of Freedom THEN Use provided (r) in the (r) table to see where the (r) would lie THEN this will provide a p-value
How do you find the p-value in a (r) table?
When your (r) value is less than a certain p-value. You would state P
What happens to (r) as (N) gets bigger?
(r) gets smaller
When reading the (r) table from Right to Left, what happens?
It gest more significant.
What happens if your (r) value is below the p-value 0.05?? Over 0.05?
It is significant
*Over 0.05 is NOT SIGNIFICANT
