Page 8 - FINAL CFA I SLIDES JUNE 2019 DAY 4
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0.1% - 0





     Example, p277/279: 2 vs 1-tailed test: A researcher has gathered data on the daily returns on a portfolio of call options over
     a recent 250-day period. The mean daily portfolio return has been 0.1% (based on same drawn), and the sample SD is
     0.25%. The researcher believes that the mean daily portfolio return is not equal to zero. Construct a hypothesis test of the
     researcher’s belief.                       2TT, p277                                                  1TT, p279














                                                                                                           Same!








                                                                     Test-                                  Same!
                                                                     stats



                                             Since 6.33 > 1.96, the sample value is significantly            Same!
                                             different from the hypothesized value

                                             Reject the Ho that the mean daily option return = 0.
                                                                                                             Same!
                                             The mean daily return of 0.001 is statistically
                                             different from 0 given the sample’s standard                   Always same?
                                             deviation and size.
                                                                                                            Statistics could be 1.78?


                                                                           Why z, and not t?
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