We have been given that Grant spent $2.50, $4.00, $4.25, and $3.25 on breakfast in one week. The next week he spent $6 more in total for the 4 breakfasts than the week before. We are asked to find increase in the mean of second week.
Since Grant spent $6 more than last week, we will divide 6 by 4 to get how much mean of second week breakfast expenditures increased with respect to first week expenditures.
Therefore, mean of second week breakfast expenditure will be $1.5 more than first week.