A large software development firm recently relocated its facilities. Top management is interested in fostering good relations with their new local community and has encouraged their professional employees to engage in local service activities. The professional employees should volunteer an average of more than 15 hours per month. A random sample of 24 professional employees reported the following number of hours per month:

12 13 14 14 15 15 15 16 16 16 16 16 17 17 17 18 18 18 18 19 19 19 20 21

Test significance level at 5% that the professional employees will be volunteer an average of more than 15 hours per month in engaging during local service activities. (a) Write the null (H0) and alternative (H1) hypothesis. (b) State the critical value of above hypothesis testing. (c) Calculate the test statistic. (d) Shall we reject the null (H0) hypothesis of these professional employees' monthly hours in volunteering during local service activities?