A journalist claims that all adults in her city spend an average of 30 hours or more per month on general reading, such as newspapers, magazines, novels, and so forth. A recent sample of 25 adults from this city showed that they spend an average of 27 hours per month on general reading. The population of such times is known to be normally distributed with the population standard deviation of 7 hours.
a. Using a 2.5% significance level, would you conclude that the mean time spent per month on such reading by all adults in this city is less than 30 hours? Use both procedures—the p-value approach and the critical value approach.
b. Make the test of part a using a 1% significance level. Is your decision different from that of part a? Comment on the results of parts a and b.