Question 1083135
Question 1:


Answer: <font color=red>choice B) ratio data</font>


Note: I'm not 100% sure on this one so I'd get a second opinion.


Explanation: The formulas used to compute the correlation coefficient r involve subtraction, squaring and division, among other operations, implying that we'll be computing ratios. With ratio data we are allowed to do this. Compare this to interval data sets where we can subtract but division and multiplication wouldn't make any sense. 


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Question 2:


Answer: <font color=red>choice D) both A and B are correct</font>


Explanation: If we know the correlation coefficient is positive, then we know that the regression line slopes upward. Likewise, if the correlation coefficient is negative, then we know that the regression line slopes downward. 


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Question 3:


Answer: <font color=red>choice A) 0.80</font>


Explanation: Take the square root of 0.64 to get 0.80. This works because 
(coefficient of determination) = (correlation coefficient)^2
(coefficient of determination) = (0.80)^2
(coefficient of determination) = 0.64
Recall that the coefficient of determination tells us how much variability of Y can be explained by X.