When interpreting the covariance between variables x and y, which of the following statements is the most accurate?
1) Covariance measures the strength and direction of the linear relationship between x and y.
2) Covariance measures the spread of the data points around the mean of x and y.
3) Covariance measures the difference between the means of x and y.
4) Covariance measures the ratio of x to y.