The amounts of time (in minutes) between eruptions of Old Faithful geyser during the first week of August 2011 are described by the histogram in Fig. 41.

a. It is a common belief that Old Faithful erupts on the hour every hour. Is this true for the first week of August 20 11?
b. Old Faithful has two types of eruptions: short and long. The long eruptions are more common and last over 4 minutes. The short eruptions last about 2.5 minutes. After a short eruption, it takes a relatively short time until the next eruption. After a long eruption, it takes a relatively long time until the next eruption. The distribution of times between eruptions could be viewed as unimodal with some outliers between 65 minutes and 70 minutes, or the distribution could be viewed as bimodal. Which viewpoint is probably better? Explain.
c. Assuming the distribution is bimodal, discuss how the distribution could be divided into two groups and identify the class that contains the median for each group.
d. Estimate the number of eruptions that occurred during the week.

Transcribed Image Text:

Times Between Eruptions of Old Faithful 35 30 25 20 E 15 10 60 70 80 90 100 110 120 Minutes