S2 - Norm Watch
- Thread Starter
- 08-04-2011 17:48
- 08-04-2011 18:01
Phi( 3-a / a ) =0.2 ...not in the table since the probabilities for positive z-values are tabulated only.
Equivalent to saying Phi( a-3 /a ) = 1-0.2=0.8
Now use the tables to see which z-value is closest to a probability of 0.8