Figure 1.

Boundary of Acceptance Regions of the Four Combination Procedures

For testing the noncentrality parameters for $Z_1,Z_2\sim {\chi }_1^2$, $H_0:{\theta }_1={\theta }_2=0$ versus $H_1:{\theta }_1\ge 0$ and ${\theta }_2\ge 0$ with ${\theta }_1+{\theta }_2>0$, the boundaries of acceptance regions of exponential (red solid), Tippett’s (blue dot-dash), Fisher’s (green dotted), and linear (black dashed) combination procedures are compared. The size of each combined test is α = 0.01.