The difference in gallons per day used is 3.6.
The formula to calculate a z-score is:

,
where X is the value used to calculate the score, μ is the mean and σ is the standard deviation. We have the z-scores so we must work backward:

For both equations, we will cancel the 1.2 by multiplying both sides:

Now we will cancel 2.2 from both equations by adding it to both sides:
3.6+2.2=X-2.2+2.2 and 0+2.2=X-2.2+2.2
5.8=X and 2.2=X
The difference in gas used per day would be given by
5.8-2.2 = 3.6.
There are 4 sets of 15 minutes in a hour so you would take the 10 airplanes and multiply it by 4 and get 40 as your answer
In 1 hour 40 planes with arrive at the airport
A quartile is a type of quantile. The first quartile (Q1) is defined as the middle number between the smallest number and themedian of the data set. The second quartile (Q2) is themedian of the data. The third quartile (Q3) is the middle valuebetween the median and the highest value of the data set.
No, i would stay with my answer #1 and trust myself.