A human resources manager at a company found that staff sent on average 22 emails per day. A manager at one of the company's branches believes that their staff on average send more than 22 emails per day. The branch manager asks a random sample staff at their branch to record how many emails they sent each day. (a) What type of statistical test would be appropriate to investigate the branch manager's prediction? (b) What is the population we can draw conclusions about in this study? (c) The branch manager believes that their staff on average send more than 22 emails per day. The branch manager conducted the appropriate hypothesis test and obtained a p-value of 0.072. Based on this result, the branch manager concluded that their staff do not send more than 22 emails per day, but they actually send 22 or less emails per day. Is this conclusion valid or not? (d) Comment on the validity of this conclusion. Provide justification for your answer.