Survival, Exponential, Accrual: Sample Size Parameters - Quick Tab

Select the Quick tab of the Survival, Exponential, Accrual: Sample Size Parameters dialog box to access options to establish the basic parameters for analyzing sample size for the test of equal exponential survival with accrual period.

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 independent (X-axis) variables in a graphical analysis will be set equal to these values.

Lambda1. In the Lambda1 box, enter the exponential parameter in group 1.

Lambda2. In the Lambda2 box, enter the exponential parameter in group 2.

Alpha. In the Alpha box, enter the type I error rate for the overall significance test.

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.

T0. In the T0 box, enter the accrual period.

T. In the T box, enter the maximum length of the follow up period.

Type of Hypothesis. Use the options buttons under Type of Hypothesis to determine the type of null hypothesis tested.

2-tailed (Lambda2 = Lambda1). Select the 2-tailed (Lambda2 = Lambda1) option button to use null and alternative hypotheses of the form

H0: l2 = l1 H1: l2 ¹ l1

1-tailed (Lambda2 <= Lambda1). Select the 1-tailed (Lambda2 >= Lambda1) option button to use null and alternative hypotheses of the form

H0: l2 l1 H1: l2 > l1