Sat 11 Jun, 2011 07:37 pm
"Is there a difference in the mean noise levels of..."
Would this imply that my alternative hypothesis is
Ha : mu (1) does not equal mu (2)
Ha : mu (1) > mu (2)
mu(1) <> mu(2)
One step at a time. If the two distributions are unequal, then test if one has a greater mean value.