Question 26 1 pts During a 15-year period, the standard deviation of annual returns on a portfolio was 6% a year. You want to study if this data is sufficient evidence to support the conclusion that the portfolio's underlying standard deviation was less than 7%. To test the hypothesis with 5% level of significance, which one of the following is correct? H, O2 0.07 one-tailed xa test with df - 14. the test-stat is 12. reject the nult hypothesis. Ho o 20.07 versus H A 0 0.0049 one-tailed x test with of - 14 the test-stat Is 10.286, reject the null hypothesis