Participants were given psychological tests measuring positive and negative affect (mood) as well as anxiety at three time periods. Time 1 was before the meditation training. Time 2 was at the end of the 8 weeks of training, and Time 3 was 4 months later. One of the results reported is:
There was a significant decrease in trait negative affect with the mediators showing less negative affect at Times 2 and 3 compared with their negative affect at Time 1 [t( 20) = 2.27 and t(21) = 2.45, respectively, p < .05 for both]. Subjects in the control group showed no change over time in negative affect (t < 1) (Davidson et al., p. 565).
The first sentence of the quote reports the results of two hypothesis tests for the mediators.
Specify in words the null hypothesis for each of the two tests. They are the same except that one is for Time 2 and one is for Time 3. State each one separately, referring to what the time periods were. Make sure you don’t confuse the population with the sample and that you state the hypotheses using the correct one.