You manage a call center that processes orders. One measure of efficiency in your department is the time spent on each call. You need to report to your superiors on the time-per-call in your call center each month. You’ve identified some of your most efficient workers, and you know that efficiency tends to decrease, in general on Fridays.
1. Identify the ethical issues involved in developing a sampling protocol:
a. There are none. It's a simple mathematical operation
b. In order to get a random and representative sample, you need to consider how efficiency fluctuates over the month, and sample call times on a frequency that includes every day of the week.
c. The analysis and reporting should consider the impact of extreme values in the data.
d. Both "b." and "c." above.

If the report is made once a month, the daily variations (including the tendency to decrease efficiency on Friday) will be masked within the monthly result.

It would only generate an ethical problem in the case that Fridays fall in different samples, but in the case of the monthly report there are usually 4 or 5 Fridays included in each sample.