I'm faced with an exercise that goes as such:
"A sample of 81 elements is taken from a population whose standard deviation is 3.
What is the approximate value of the mean's sample deviation, in percentage?"
I can then pick from a list of choices:
- 54%
- 12%
- 67%
- 20%
- 33%
I know for a fact that the right answer is 33%, but I can't figure out why.
When hearing about "standard deviation in percentage" I instantly think of multiplying the standard deviation's value by 100 and dividing that by the mean/average, the problem being I'm not given the mean. How do I go about this?