In reviewing the data in the Performance Lawn Equipment

Database, Elizabeth Burke noticed that defects received

from suppliers have decreased $($worksheet Defects After

Delivery$).$ Upon investigation, she learned that in $2014,$

PLE experienced some quality problems due to an increas$-$ing number of defects in materials received from suppli$-$ers. The company instituted an initiative in August $2015$

to work with suppliers to reduce these defects, to more

closely coordinate deliveries, and to improve materials

quality through reengineering supplier production policies.

Ms$.$ Burke noted that the program appeared to reverse an

increasing trend in defects; she would like to predict what

might have happened had the supplier initiative not been

implemented and how the number of defects might further

be reduced in the near future.