QUESTION 2 A lunch bar has an average sales amount of $8.5. The manager initiates staff training to try to get them to sell more extras (chips, drinks etc), and after this training, a sample of 40 customers had the following sample statistics: x = 9.02 and s = 2.7 Assume our question of interest is: "is there significant evidence that the mean amount spent by customers has increased?" Calculate the observed value of the test statistic (correct to 2dp)