We draw a simple random sample of 40 bills from a restaurant (representing 40 tables

served).The population is the set of 300 bills for the week.For each invoice, we

note:

X: the number of people served

Y: the amount of the invoice

We plan to take a sample next week to estimate certain parameters.We

assumes that the number of invoices will not have changed - it will remain 300

Now suppose that all prices will be marked up by 15% [without affecting the

consumption].Determine the size of the sample that will need to be drawn so that the margin of error in

the estimated total revenue is $ 4,000.

Here is a summary of sample data: Number of persons Amount of served by invoice (X) invoice (Y) Sum 80 2,699.11 Corrected variance 1.47 1,876.84