Select the Quick tab of the
Independent
Sample t-Test: Power Calculation Parameters dialog box to access options
to establish the basic parameters for analyzing power for the independent
sample t-test.

Fixed Parameters. The entries in the boxes under Fixed Parameters establish the values for the fixed parameters in the power calculation.

Mu1. Enter the mean for the population from which group 1 was sampled in the Mu1 box.

Mu2. Enter the mean for the population from which group 2 was sampled in the Mu2 box.

N1. Enter the sample size for group 1 in the analysis in the N1 box.

N2. Enter the sample size for group 2 in the analysis in the N2 box.

Alpha. Enter the Type I error rate used in determining the critical value for the t-statistic in the Alpha box.

Sigma. Enter the population standard deviation for the population sampled from in the analysis in the Sigma box.

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

2-tailed (Mu1 = Mu2). Select the 2-tailed (Mu1 = Mu2) option button to use null and alternative hypotheses of the form

H0: μ1 = μ2 H1: μ1 ¹ m2

1-tailed (Mu1 <= Mu2). Select the 1-tailed (Mu1 <= Mu2) option button to use null and alternative hypotheses of the form

H0: μ1 ≤ m2 H1: m1 > m2

1-tailed (Mu1 >= Mu2). Select the 1-tailed (Mu1 >= Mu2) option button to use null and alternative hypotheses of the form

H0: μ1 ³ m2 H1: m1 < m2