Part 1
The questions in Part 1 refer to the data in the file
'fastfood2.csv'. The file has several columns: "storenum"
gives the store number, "secs" that gives the number of seconds
to fill the order, "dayofweek" gives the day of the week,
"meal" gives which meal ordered, "drinkonly" is Yes if only
a drink was ordered, "cost" gives the amount spent in cents.
(a) Determine the proportion of meals that were for Lunch.
(b) Determine the mean time for each day of the week.
(c) Find a 95% confidence interval for the proportion of "drink only"
orders for each of Breakfast, Lunch, and Dinner. Does there appear
to be any difference among the three meals?
(d) Find the mean cost for each of the meal types.
(e) Find the proportion of meals of each type, for each day of the week.
(f) Identify all stores with average order fill time 2 standard
deviations below the mean average fill time for the 892 stores.
(These are the high performing stores.) Similarly, identify all
stores with average order fill time 2 standard deviations above
the mean average fill time for the 892 stores. (These are the
low performing stores.). For each, sort the store number from
smallest to largest.
Note: Here the standard deviation is of the set of 892 store
averages, not of the 100,288 separate order times.
(g) Some stores claim that using the mean is unfair due to outliers.
Repeat part (f) using the median in place of the mean, and determine
which stores (if any) are in both "high performing" groups or both
"low performing" groups.
NOTE: Assignment 5 is in two parts. Assignment 5b will be posted soon.
