Investigation 3: Waiting for Old Faithful (due Wed, Jan 18)

You may work with one other person on this assignment, handing in one report with both names.  Word-processed reports are preferred to hand-written ones.  Please copy/paste relevant, well-labeled Minitab output into a Word file as appropriate.

The Minitab worksheet OldFaithful7803.mtw contains data on inter-eruption times (times between eruptions, measured in minutes) for Old Faithful geyser in Yellowstone Park. Some of these times are taken from 1978 and some from 2003. Note that the file contains the data both in “stacked” form (c1 and c2) and in “unstacked” form (c4 and c5).

a) Use Minitab to produce boxplots and descriptive statistics for comparing the inter-eruption times in 1978 to those in 2003. Submit the graph and the five-number summary for each year.

b) Comment on how the center of the distribution of inter-eruption times compare between these two years. Discuss implications for tourists of how they compare.

c) Comment on how the variability (spread) of the distribution of inter-eruption times compare between these two years. Discuss implications for tourists of how they compare.

d) Examine a histogram of the distribution of inter-eruption times for each year. Comment on a feature of shape that the histogram reveals but the boxplot did not. Compare the two years on this feature.