Question

We wanted to build the power function to the following case:

H₀: μ≥ 4.25, H_A: μ <4.25, n = 81, σ = -1.8, α = 0.01

After considering the information above and the graph in Figure 1, Exactly two errors were observed. Identify the errors and after the correct corrections, what conclusions can be drawn?

4.4 4.6 4.85.0 5.2 5.4 5.6 Valores alternativos para la media Figura 1: Curva de potencia

Answer 1

The first error is that sigma reported negative. Sigma is always positive.

Another error is that the value of the powers are reported for mu>4.25, that is under the null•

The test is faulty as it can not control the type 1 error probability at .01 at mu=4.25.