River Run campground has sites for people to use for camping. The sites can be reserved for a certain number of days. To help with cleaning and maintenance, the campground requests an exit time (the time at which campers leave the site) of 9 A. M. on the last day of the reservation.

To estimate the typical exit time, the manager of River Run selected a random sample of 60 sites. Of the selected sites, 40 were reserved by people without young children, and 20 were reserved by people with young children. The following histograms summarize the exit times, recorded as minutes relative to 9 A. M. For example, an exit time of 9:30 A. M. is 30 minutes relative to an exit time of 9 A. M. Each interval contains possible values from the left endpoint up to but not including the right endpoint.

(a) Consider the two histograms.
(i) How many of the 60 sites had an exit time before 8:30 A. M.?

(ii) How many of the 60 sites had an exit time of 11:00 A. M. or later?

(b) Compare the distributions of the exit times for those without young children and those with young children.

(c) Based on the histograms, what is a reasonable estimate of the median exit time for the random sample of 60 sites? Explain your reasoning.

Answer:

a.

i. two

ii. eight

Explanation:

(a) Consider the two histograms.

i. From the histogram -60 minutes indicates a one hour behind 9.am thus it allows the category that left before 8.30am.

ii. From the histogram from 120 minutes and above indicates a two hour ahead of 9.am thus it allows the category that left 11.am upwards.

(b) For those with children they could not meet up with the exit time as the distribution shows that most of them exited after 9.am.

However, for those without children in about two sites they met up with the 9.am exit time.

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