Free Lunch?

Many restaurants have a policy of 30 minutes or free for lunch. How much of a risk is this for the restaurant? How fast do meals arrive? To investigate this, the waiting times (minutes) between the time an order was taken and when the meal arrived was observed over several weeks in a number of different outlets of a popular franchise over the last fall. Here is the actual (sorted) data collected.

12.7 13.8 13.8 14.6 14.8 15.6 15.7 15.8 15.9 16.0

16.1 16.6 16.8 16.9 17.1 17.1 17.5 17.8 17.9 18.0 18.3 18.6 19.9 20.0 20.1 20.4 20.5 20.8 21.1 21.2

21.3 21.3 21.7 21.8 22.1 22.5 22.5 23.1 23.1 23.2

23.5 23.6 23.7 23.9 24.1 24.8 24.8 25.1 31.5 39.2

What is the population of interest?

The data is reported to one decimal place. Is this realistic and meaningful?

Why was the data collected over a period of time in different outlets?

What is an estimate of the proportion of meals that take longer than 30 minutes?

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