Question 16 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? Hoo? 0.07. one-tailed y? test with df - 14, the test-stat is 12 reject the null hypothesis. Hoo? > 0.07 versus H o? 0.0049. one-tailed x test with df - 14, the test-stat is 10.286, reject the null hypothesis