Question 6 is unclear. There really is no rule stating whether midnight is meant to correspond to the start or the end of the day. In fact, with conventions, it's more common for midnight to be assumed as the start of the day. So to obtain the required answer (this is based off a real life event), it would make more sense to say it happened at midnight on
30 December 2011.
Question 8 is unclear in what they want in my opinion. In reality, \(R^2\) values should be here. But the syllabus has already said that students are not expected to compute it; only use it.
The next bet is then the correlation coefficient, but again this is a lot of work for just 3 marks. Plugging into what's given on the formula sheet takes HEAPS of effort. On the other hand, if it was intended that a calculator be used, what is the purpose of having the formula on the sheet?
Between Q7 and Q8 - why does the 7 mark question have more writing space than the 3 mark question?
Question 9 gives way too little marks for the forecasting. The seasonal adjustments required in the process and the fact that
multiple least squares lines must be fit is at least as tedious as something like Question 7 with the table of values work. (Also similar to other methods of solving Q7.)