Question 287179
 Suppose we want to test null hypothesis H0:&#956; =400 against H1:&#956; <400. The test statistic is calculated as -1.23 and two-tailed critical value is 1.96. The appropriate p-value will be?
------------
Comment: With H1: u <400 you do not have a two-tailed test; you have 
a left tailed test.  The p-value would be the area to the left of 
the test statistic.
P(z< -1.23) = normalcdf(-100,-1.23) = 0.1093
============
I used a TI calculator.
============
The problem would require a two-tailed test if H1 was "u is not equal
to 400".  In that case the p-value would be 2*P(z<1.23) = 0.2187
=====================
Cheers,
Stan H.