The data represent the number of phone calls received over a 70day period.

Day 1 2 3 4 5 6 7

Calls Received 5 2 9 8 3 1 0

What is the mean number of phone calls received?

Are you talking about 7-day period instead? Or is that really 70?

Anyway, the mean number of phone calls received over the period of time given would be 4 calls. I got to this answer through adding all of the calls and dividing them by the number of days.