Random samples of monthly rent prices, in dollars, for studio and one-bedroom apartments, were obtained for the Pennsylvania cities of Harrisburg and Philadelphia in July 2007. A 90% confidence interval for the difference in population means µH - µP turns out to be
( -$261.1, -$22.3 ).
1. Write a sentence or two interpreting what this interval reveals about the average difference between rents in Harrisburg and Philadelphia.
2. Determine the midpoint of this interval.