3 The table shows, for each of a random sample of 7 weeks, the number of customers, \(x\), who purchased fuel from a filling station, together with the total volume, \(y\) litres, of fuel purchased by these customers.
| \(\boldsymbol { x }\) | 230 | 184 | 165 | 147 | 241 | 174 | 210 |
| \(\boldsymbol { y }\) | 4551 | 3410 | 3252 | 3756 | 3787 | 4024 | 4254 |
- Calculate the equation of the least squares regression line of \(y\) on \(x\).
- Estimate the volume of fuel sold during a week in which 200 customers purchase fuel.
- Comment on the likely reliability of your estimate in part (b), given that, for the regression line calculated in part (a), the values of the 7 residuals lie between approximately - 415 litres and + 430 litres.