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Question 6.17: Refer to Example 6.16. Find the sample size needed so that t...

Refer to Example 6.16. Find the sample size needed so that the power will be at least 0.9.

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The following computer output (from MINITAB) presents the solution:

Power and Sample Size

1- Sample t Test

Testing mean= null (versus > null)
Calculating power for mean = null + difference
Alpha = 0.05  Assumed standard deviation = 1.5

Sample        Target

Difference            Size              Power            Actual Power

2                      7                  0.9                  0.926750

The smallest sample size for which the power is 0.9 or more is 7. The actual power is 0.927.

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