7 A random sample of twelve pairs of values of \(x\) and \(y\) is taken from a bivariate distribution. The equations of the regression lines of \(y\) on \(x\) and of \(x\) on \(y\) are respectively
$$y = 0.46 x + 1.62 \quad \text { and } \quad x = 0.93 y + 8.24$$
- Find the value of the product moment correlation coefficient for this sample.
- Using a \(5 \%\) significance level, test whether there is non-zero correlation between the variables.