The article “Supply Voltage Quality in Low-Voltage Industrial Networks of Estonia” (T. Vinnal, K. Janson, et al., Estonian Journal of Engineering, 2012:102–126) presents voltage measurements for a sample of 66 industrial networks in Estonia. Assume the rated voltage for these networks is 232 V. The sample mean voltage was 231.7 V with a standard deviation of 2.19 V. Let μ represent the population mean voltage for these networks.

a. Find the P-value for testing H₀ :μ = 232 versus H₁ :μ ≠ 232.

b. Either the mean voltage is not equal to 232, or the sample is in the most extreme % of its distribution.