EXAMPLE 12.22

Testing the second contrast of interest. The sample contrast that estimates ψ2 is

= (0.5)2.405 + (0.5)2.615 + (−1)1.600

= 1.2025 + 1.3075 − 1.600

= 0.91

with standard error

= 0.2435

The t statistic for assessing the significance of this contrast is

The P-value for the two-sided alternative is 0.0003. If we used Table D, we would conclude that P < 2(0.0005) = 0.001. The P-value is very small, so there is strong evidence against H₀₂.