Answer:
32.793
Explanation:
Given that your marketing colleague used a known population mean and standard deviation to compute the standard error as 56.8 for samples of a particular size
You don't know the particular sample size but your colleague told you that the sample size is greater than 60.
When n becomes 3n, we get Std error would become instead of

to

Thus we get standard error for new sample size = old se/sqrt 3
=
