The null hypothesis is that we are sampling from a population with a mean of 500 and standard deviation of 100 (H0: m = 500). With α set at .05, we use the p–z converter, we find that the z-score which corresponds to a one-tailed p-value of .05 is 1.645. We can use this z-score to calculate the critical value for a sample mean for a particular sample size, in this case, 25.
