Compute the coefficient correlation. (Negative values should be indicated by a minus sign. Round sx, sy and r  to 3 decimal places.)   x y x−x¯x-x¯ y−y¯y-y¯ (x−x¯)2x-x¯2 (y−y¯)2y-y¯2 (x−x¯) (y−y¯)x-x¯ y-y¯ 2 15   −9   81   4 25 1   1   1 1 10   −14   196   5 40 2   4   32 3 30   6 0   0 ? ?     ? ? ?

Below is data for two variables, X and Y.  Answer the questions that follow.  X Y X-MX Y-MY (X-MX)2 (Y-MY)2 (X-MX)(Y-MY) 3 3 -2 -1 4 1 2 4 3 -1 -1 1 1 ___ 6 4 1 ___ 1 0 0 7 6 2 2 ___ 4 4   What is the missing value under the (X-MX)(Y-MY) column? (far right column)

Calculate the correlation coefficient r, letting Row 1 represent the x-values and Row 2 the y-values. Then calculate it again, letting Row 2 represent the x-values and Row 1 the y-values. What effect does switching the variables have on r? Row 1 19 23 31 49 51 70 79 Row 2 156 155 190 141 202 191 181 Calculate the correlation coefficient r, letting Row 1 represent the x-values and Row 2 the y-values. r= 0.430 (Round to three decimal places as needed.) Calculate the correlation coefficient r, letting Row 2 represent the x-values and Row 1 the y-values. (Round to three decimal places as needed.)

The following data is the number of tickets sold and the jackpot value for the Mega Millions lottery. The jackpot value is in millions of dollars and the number of tickets sold is in millions. Jackpot value 334 127 300 227 202 180 164 145 255 Number of tickets sold 54 16 41 27 23 18 18 16 26 r= 0.947 tickets sold -10.87 +0.17 (jackpot value) Which is the independent variable and which is the dependent variable? X= independent variable = Y= dependent variable Interpret ². Interpret the slope. Predict the number of tickets sold when the jackpot value is 500 million dollars. Would you feel comfortable using the model for this value? Why or why not.

Below is data for two variables, X and Y.  Answer the questions that follow.  X Y X-MX Y-MY (X-MX)2 (Y-MY)2 (X-MX)(Y-MY) 3 3 -2 -1 4 1 2 4 3 -1 -1 1 1 ___ 6 4 1 ___ 1 0 0 7 6 2 2 ___ 4 4   What is the missing value under the (X-MX)2 column?

Below is a scatter plot of observations of 2 variables. Which statement is true? 20 15 10 5 0 -3 The covariance is negative The covariance is positive X and Y are independent The covariance is 0 -2 -1 0 X 1 2 13 3 4