Select the Quick tab of the One Variance: Sample Size Parameters dialog box to access options to establish the basic parameters for analyzing sample size for the one variance chi-square test.

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.

Var.

Var0. In the Var0 box, enter the null hypothesized variance.

Alpha. In the Alpha box, enter the type I error rate (a) used in determining the critical value for the chi-square 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 is greater than or equal to this value.

Type of Hypothesis. The choice of option buttons under Type of Hypothesis determines the type of null hypothesis tested by the chi-square statistic.

2-tailed (Var = Var0). Select
the 2-tailed (Var = Var0) option
button to use a null and alternative

H0:
σ2 = σ20

1-tailed (Var <= Var0). Select
the 1-tailed (Var <= Var0)
option button to use a null and alternative

H0:
σ2
≤ σ20

1-tailed (Var >= Var0). Select
the 1-tailed (Var >= Var0)
option button to use a null and alternative

H0:
σ2 ³ s20