When looking at the differences of two means, it is important to identity if the sampling is independent or dependent. Consider the situation below and then answer the question that follows.  In low-speed crash test of five BMW cars, the repair costs were quoted for a factory authorized repair center and an independent repair center. A manager of BMW wants to determine if the independent center has lower repair costs using a hypothesis test. 
Authorized repair center: $797, $571, $904, $1147, $418
Independent repair center: $523, $488, $875, $911, $297

The manager is trying to determine if he should: Afind the mean of the 5 authorized repair center quotes and the mean of the 5 independent repair center quotes and compare the difference of the two means, OR Bfind the mean of the differences of the two quotes for each car.

Which do you think he should choose?​