Calculate, if you haven$$t done so already, the overall averages for $($i$)$ probability of booking and $($ii$)$

CPC across all publishers. Note that the overall averages should not be calculated by averaging the

averages of all the publishers. For example, to get an overall average of CPC$,$ you will have to

divide the aggregate costs across all the publishers by the aggregate number of clicks $($you get these

numbers in the last row of the pivot table$)$ NOT by averaging the calculated CPCs for each

publisher. A similar calculation will need to be applied for the overall probability of booking$).$