Yes, questions could be pointing to both 1-tail or 2-tail tests. So, it will be good to memorize standardized z values for both for mosty used confidence intervals. (90, 95 and 99)
But most common 1-tail z characteristic asked for is at 95% confidence, which is same as that for 2-tail at 90% confidence. (i.e. 1.65). And you will be expected to know it as they will not be providing its value in the question.
I dont remember having to use 1-tail value for 90% or 99% in CFA exam or in any practice questions though.
If they don't tell you directly which test to use you should be able to infer based on the null+alternative hypothesis: does not equal vs. great/less than.
发表于 2011-7-13 15:17
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