A cup manufacturer needs to validate that the units produced have approximately the same diameter. An analysis was made, samples were taken every three hours of work and the diameter of each was noted (in cm).

6h	9h	12h	15h	18h
9	10	7	10	7
8	10	9	4	7
10	10	5	10	13

a. Determine all the values needed to make a map of the averages. Detail your calculations, but do not draw the map.

b. Is the process under control or out of control? Do not draw the map. Justify your answer by analyzing the data and your answer to the previous question.