Correlation & Regression Flashcards
What is the correlation equation?
r = Sxy/Sx.Sy
Sxy = how much x & y change together
Sx.Sy = how much x & y change seperately
What 2 things does the r value tell you?
1 ) what direction your correlation is
2) how strong your correlation is
if r is above zero, is your correlation positive or negative?
Positive
if r is close to 1, is your correlation strong or weak?
Strong
What does the r2 (r-squared) value tell you?
How much of the variance is explained by correlation
What does it mean if r2 is close to 1?
Your correlation explains A LOT of variance
What equation is important to remember with straight line graphs?
y = mx + c
When x = 0, what does y = ?
y = intercept
if Zola is 0 cm tall… she will weigh ~3.8kg!
When x increases by 1, what does y increase by?
y increases by the slope
Correlation vs Regression: which describes a single relationship?
Correlation, regression describes multiple relationships
Correlation vs Regression: which are X and Y not interchangable for?
Regression - correlation x and y are interchangable
Correlation vs Regression: which allows prediction
Regression - correlation DOES NOT allow prediction
