The answer is 7
There is no need for explaining cause you can minus -2 and 5 to get x+7
3.19 - 1.99 = 1.20 increase in 4 years
1.20/4 = 0.30
rate of change is 0.30 per year (30 cents per year)
0.156 because you take 3.9 (fudge) and divide it by 25 (guests)
True.
If the standard deviation value is larger, it means the data points are further away from the mean - which indicates that the data in the set are more variable.