Two Correlations: Power Calculation Parameters - Quick Tab

Select the Quick tab of the Two Correlations: Power Calculation Parameters dialog box to access options to establish the basic parameters for analyzing power for the Z-test for comparing two correlations.

Fixed Parameters. The entries in the boxes under Fixed Parameters establish the fixed, or baseline, parameters for subsequent power calculations and graphs. Parameters that are not varied explicitly as the dependent (X-axis) variables in a graphical analysis will be set equal to these values.

Rho1. In the Rho1 box, enter the hypothetical value of the population correlation for the first experimental population.

Rho2. In the Rho2 box, enter the hypothetical value of the population correlation for the second experimental population.

N1. In the N1 box, enter the sample size for the group sampled from the first experimental population.

N2. In the N2 box, enter the sample size for the group sampled from the second experimental population.

Alpha. In the Alpha box, enter the type I error rate used in determining the critical value for the Z-statistic.

Type of Hypothesis. Use the option buttons under Type of Hypothesis to determine the type of null hypothesis tested by the Z-statistic.

2-tailed (Rho1 = Rho2). Select the 2-tailed (Rho1 = Rho2) option button to use null and alternative hypotheses of the form

H0: r1  = r2    H1: r1 ¹  r2

1-tailed (Rho1 <= Rho2). Select the 1-tailed (Rho1 <= Rho2) option button to use null and alternative hypotheses of the form

H0: r1 r2    H1: r1  >  r2

1-tailed (Rho1 >= Rho2). Select the 1-tailed (Rho1 >= Rho2) option button to use null and alternative hypotheses of the form

H0: r1  ³  r2    H1: r1  <  r2