Consider a large number of countries around the world.  There is a positive correlation between the number of XBox One games per person x and the average life expectancy y.  Does this mean that we could increase the life expectancy in Somalia by shipping XBox One games to that country?   A. It makes no sense to calculate the correlation between these variables.   B. Yes. The correlation says that as the number of XBox One games per person goes up, so does life expectancy.   C. No. If the correlation were negative, we could accept that conclusion, but this correlation is positive.   D. Yes. Positive correlation means that, if we increase x, then y will also increase.   E. No. The positive correlation just shows that richer countries have both more XBox One games per person and higher life expectancies.

The following statement contains an error. Choose the statement that best explains the error. "The correlation between shoe size and height is 0.87 inches" A. Correlation requires that both of the variables be categorical B. When stating the correlation coefficient, one must state whether it is a positive or negative relationship C. This statement does not tell us whether or not shoe size is correlated with height D. When reporting correlation, one does not report units because correlation has no units E. There is no error in this statement

Suppose the correlation between height and weight for adults is +0.80. What proportion of the variability in weight can be explained by the relationship with height? A. 20% B. 36% C. 64% D. 80%

An economist wants to determine whether there is a linear relationship between a country's gross domestic product (GDP) and carbon dioxide emissions. The data are shown in the table below. c. Compute and interpret the correlation coefficient. d. Compute and interpret the coefficient of determination. e. Test for the significance of the linear relationship. Use a 0.05 level of significance. State your conclusion. Hint: Your conclusion is either of the following. • There is a significant linear relationship between a country's gross domestic product (GDP) and carbon dioxide emissions. • There is no significant linear relationship between a country's gross domestic product (GDP) and carbon dioxide emissions. GDP 1.6 3.6 4.9 1.1 0.9 2.9 2.7 2.3 1.6 1.5 (trillion dollars) Carbon Dioxide Emissions 428.2 828.8 1214.2 444.6 264 415.3 571.8 454.9 358.7 573.5 (millions of metric tons)