Two variables are correlated with r=−0.31.

which answer best describes the strength and direction of the association between the variables?

weak positive
weak negative
strong negative
strong positive

weak negative

Step-by-step explanation:

we know that

The correlation coefficient r measures the direction and strength of a linear relationship. It can take a range of values from +1 to -1.

Values between -0.5 and -1.0 or 0.5 and 1.0 indicate a strong negative/positive linear relationship

Values between -0.3 to -0.1 or 0.1 to 0.3 indicate a weak negative/positive linear relationship

In this problem

The correlation coefficient for the data is −0.31

therefore

Is a weak negative correlation

constant of proportionality = 3 and the equation is c = 3p.

step-by-step explanation:

c = kp   where c = amount of caffeine in mg., p = oz of pepsi and k is the constant of proportionality.

substituting the values given:

24 = 8k

k = 3.

the same value of k will be obtained if we substitute the other given values.