Question

Compute a sample size calculation that will provide sufficient power (80% at the 95% significance level)

Answer 1

Example:

The mean water temperature downstream from a power plant cooling tower discharge pipe should be no more than 100°F. It is assumed that the water temperature follows a normal distribution with parameters µ and σ. An environmental engineer is interested in the following hypothesis:

H₀: µ = 100°F

H₁: µ > 100°F

Past experience indicates that the standard deviation, of temperature is 4°F.

A sample size caclulation to detect a true mean of 102°F if we wanted the power of the test to be at least 80% is given below.

We need ()

The sample size would be required to detect a true mean of 102°F is .