Construct a 90% confidence interval estimate of the reduction in playing time at the golf course (see Exercise 23 above).
In exercise
A golf course was concerned that many of its golfers were playing too slowly, thus reducing the number of players the course could host (and profits). The course marshal recorded the time (in minutes) for randomly selected foursomes in the ladies' league to play nine holes (walking). The marshal then implemented measures designed to encourage greater speed of play, and recorded the playing time for the same foursomes. Is there sufficient evidence, at the 5% level of significance, to conclude that the new approach increased the speed of play at the course?