For a random sample of 5 pairs of values of \(x\) and \(y\), the equations of the regression lines of \(y\) on \(x\) and \(x\) on \(y\) are respectively
$$y = - 0.5 x + 5 \quad \text { and } \quad x = - 1.2 y + 7.6$$
Find the value of the product moment correlation coefficient for this sample.
Test, at the \(5 \%\) significance level, whether the population product moment correlation coefficient differs from zero.
The following table shows the sample data.
| \(x\) | 1 | 2 | 5 | 5 | \(p\) |
| \(y\) | 5 | 3 | 4 | 2 | \(q\) |
Find the values of \(p\) and \(q\).