Identify the true statements about the correlation coefficient, r.
a.) The correlation coefficient is not affected by outliers.
b.)The value of r ranges from negative one to positive one.
c.) When the data points in a scatter plot fall closely around a straight line that is either increasing or decreasing, the correlation between the two variables is strong.
d.) A correlation coefficient of zero means that no relationship exists between the two variables.
e.) If two variables are positively correlated, when one variable increases, the other variable decreases.
f.) The sign of r describes the direction of the association between two variables.