Final answer:
To find the critical value, subtract the significance level from 1 and then find the corresponding z-score in the standard normal distribution table. Compare the test statistic with the critical value to determine whether to reject or fail to reject the null hypothesis.
Step-by-step explanation:
a. To find the critical value(s), we need to determine the cutoff point that separates the critical region from the non-critical region. Since this is a right-tailed test, the critical value will be on the right side of the distribution. Using a 0.10 significance level, we can find the critical value by subtracting the significance level from 1 and then finding the corresponding z-score in the standard normal distribution table.
b. To determine whether to reject or fail to reject the null hypothesis (H0), we compare the test statistic (z = 2.27) with the critical value(s) we found in part (a). If the test statistic is in the critical region (greater than the critical value), we reject H0. If the test statistic is not in the critical region (less than or equal to the critical value), we fail to reject H0.