1) A comparison is made between summer electric bills of those who have central air and those who have window units.

Find the mean and median for each of the two samples, then compare the two sets of results.

May June July Aug Sept

Central $32 $64 $80 $90 $65

Window $15 $84 $99 $120 $40

2) The 10% trimmed mean of a data set is found by arranging the data in order, deleting the bottom 10% of the values and the top 10% of the values and then calculating the mean of the remaining values. What advantages do you think that the trimmed mean has as compared to the mean?

3) The textbook defines significantly low or high values as those data points with z scores less than z = -2.00 or z scores greater than z = 200. Comment on this definition with respect to Chebyshev's theorem; refer specifically to the percent of scores which would be defined as significant according to Chebyshev's theorem.

4) The table below provides a frequency distribution for the winner of the Davis Cup Tennis Competition during the period 1977-1994.

Winner of

Davis Cup Frequency

United States 6

Germany 3

Czechoslovakia 1

Australia 3

France 1

Sweden 4

Which measure of center, the mean, the median, or the mode is most appropriate here? Why?

5) An engineer is designing a machine to manufacture gloves and she obtains the following sample of hand lengths (mm) of randomly selected adult males. A frequency distribution is created from the data.

The frequencies in order are 1, 8, 56, 237, 382, 228, 48, 4, 1. Does it appear that the sample is from a population with a normal distribution? Explain.