The following table shows the annual returns (in percent) for the Vanguard Energy Fund. Year Return 2010..............13

Question:

The following table shows the annual returns (in percent) for the Vanguard Energy Fund.
Year Return
2010..............13
2011..............-2
2012...............3
2013..............18
2014............-14
Source: finance.yahoo.com, data retrieved April 4, 2015.
a. Calculate the point estimate for μ.
b. Construct the 95% confidence interval for μ.
c. What assumption did you make when constructing the interval?