Answer
Jill
Solution
The figure attached with this question shows the performance of five teachers at Oakdale middle school.
It shows five year chart (2005 - 2009).
Teachers are Jill, Ed,Ralph,Tina and Sam.First consider performance of Jill, performance vary only in 2006 and all other years the performance is consistent.In the case of all other teachers their performance vary inconsistently.
So the teacher Jill Exhibited the most consistent performance over the 5 year span
