- CFA Exams
- CFA Level I Exam
- Topic 1. Quantitative Methods
- Learning Module 8. Hypothesis Testing
- Subject 7. Test of a Single Mean
CFA Practice Question
The standard deviation of a large population is 20. To test:
H(0): μ <= 4 vs. H(A): μ > 4
At level of significance .05, a sample size of 100 will be taken. You will reject H(0) if ______.
A. XBAR >= 7.3
B. XBAR >= 7.8 or XBAR <= .2
C. XBAR >= 7.8
Explanation: Z = (XBAR- μ)/(S/SQRT(n))
1.645 = (XBAR - 4)/2
XBAR = 7.29
1.645 = (XBAR - 4)/2
XBAR = 7.29
User Contributed Comments 5
User | Comment |
---|---|
jpducros | Where does that 1,645 is coming from ? |
jpducros | ok, my mistake, I still have difficulties in remembering all the principal thresholds. |
Jurgen | It comes from the z table. Given that the significance level is 0.05, we are looking for the 0.95 level which gives a z of 1.65. |
lawlee | Isn't this a two-sided test with z=1.96? |
kimmykim23 | lawlee if the Ho was stated as = 4 then it would be a two tailed test. But since it's <= it's a one tailed test. |