Piano teachers have the option to put their students through student achievement testing
where they are formally judged based on their piano skills. One of the judged areas is sight-
reading where students must try to play a section of sheet music they have never seen before.
Suppose a judge is trying to compare the difficulty of two separate sight-reading pieces. What
follows is a random sample of sight-reading scores out of 20 points from the same judge.
Assume the scores follow an approximately normal distribution.
Sight reading piece #1
12 11 16 20 4 11
5 8 16 15 16 12
Sight reading piece #2
18 8 18 19 15 20 20 17 16 12 18 12
12 19 15 12 12 15 16 13 20 17 15 19 13 15
a. Describe the population parameter (hint: it relates to the difference of two parameters)
b. Find the appropriate 99% confidence interval.
