CFA Practice Question

There are 434 practice questions for this study session.

CFA Practice Question

The manufacturer of a sore throat spray claims that the product brings pain relief to sore throat sufferers within 5 seconds of contact. The manufacturer reported that for a random sample of 100 sore throat sufferers, the mean time of relief was 3.2 seconds with a standard deviation of 1 second. Find the rejection region for the test if testing at z < z0.01.
A. z < z0.01 = -2.33
B. z < z0.01 = -1.96
C. t < t0.01 = -3.18

User Contributed Comments 8

User Comment
danlan How to get this?
hizmo Look at the z table.
julamo Do we really need to know those z-table values by heart??? Doesn't make any sense
Xocrevilo A reference page I use for practice questions. The same values keep on preparing, thus eventually you should hardly need to refer to it at all:

http://www.stat.tamu.edu/stat30x/zttables.html
mishis I thought this meant that Alpha was 2% so .9800 in Z table is 2.06. Anyone?
Mariecfa This is a left tailed test. Look at the Z Table: Negative Values for the area .01 to find the Z Value which is -2.33.

Also if you know that the area (0.01) which is to the left of the test statistic Z, you can subtract that value of 0.01 to get a 99% Confidence Interval that would give you -2.33 for the Z Value on the left tail from remembering the common 99% Confidence Interval is 2.33 for the Z Value. You would not have to look at a Z table.
bhaynes It is key that you memorize these values for a one-sided z-test.....

99% - 2.33
95% - 1.645
90% - 1.28

For two sided:

99% - 2.58
95% - 1.96
90% - 1.645
zzhumanov thank you Bhaynes
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