A shareholders' group, in lodging a protest, claimed that the mean tenure for a chief executive office (CEO) was at least eight years. A survey of companies reported in the Wall Street Journal found a sample mean tenure of 7.68 years for CEOs with a standard deviation of 6.36 years. a. Formulate hypotheses that can be used to challenge the validity of the claim made by the shareholders' group.- Select your answer -- Select your answer -b. Assume companies were included in the sample. What is the -value for your hypothesis test