Which of the following statements concerning the correlation coefficient (r) are true?

it is a unitless measure of the linear association between two variables

the range of values it can take is not restricted

a strong linear relationship, either positive or negative, between two variables indicates that one variable must cause changes in the other variable

the correlation coefficient can take the value of -1 or 1, or any value between -1 and 1.

r = 0 indicates there is no linear relationship between the two variables

r = -1 indicates that all points on a scatter diagram could be connected by a downward sloping straight line

r = -0.7 indicates a stronger linear relationship between the variables than if the correlation coefficient were -0.4