"Based on the Test Score Average of 85% at Washington

Essay

"Based on the test score average of 85% at Washington Elementary School, I would say scores for the whole district are in the 82% to 88% range, with 95% confidence."
A) Why does the person say, "Scores for the whole district will be in the 82% to 88% range," rather than give a definite percent?
B) Using the quote, put the correct percents for test score average in the blanks to the right in the diagram below.