Two Correlations: Sample Size Parameters - Quick Tab

Select the Quick tab of the Two Correlations: Sample Size Parameters dialog box to access options to establish the basic parameters for analyzing sample size 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 sample size 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.

Alpha

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

Power Goal

In the Power Goal box, enter the minimum acceptable power, for which a minimum sample size is calculated. If the search for an acceptable sample size is successful, the actual power of the statistical test will be greater than or equal to this value.

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