WHAT IS THE CRITICAL ZSCORE THAT MARKS THE TWOTAILED ALPHA

WHAT IS THE CRITICAL Z-SCORE THAT MARKS THE TWO-TAILED, ALPHA = 1% (99% CONFIDENCE) SPLIT WITH 0.005 AT EACH END (0.995 TO THE LEFT OF THE +Z-SCORE)

Solution

For a two tailed 0.01 test, there is an area of 0.005 on each tail.

Using table or technology to get the z score for this left tailed area,

zcrit(left end) = -2.575829304 [ANSWER]

Also, by symmetry, the right end of this is

zcrit(right end) = 2.575829304 [ANSWER]