1. A report gives the covariance between the number of employees at an assembly factory and the total number of items produced daily. The covariance would be larger if these data were aggregated to monthly totals.
2. The correlation between sales and advertising when both are measured in millions of dollars is 0.65. The correlation remains the same if we convert these variables into thousands of dollars.
3. A gasoline station collected data on its monthly sales over the past three years along with the average selling price of gasoline. A scatterplot of sales on price of gasoline showed positive association. This association means that higher prices lure more customers.
4. Half of the numbers in a correlation matrix are redundant, ignoring the diagonal.