Question: Several years ago a new chief executive was appointed to a group of firms. On appointment the CE expressed concern about the quality of the senior management in one of the major companies in the group. He felt that this group of managers was by and large out of touch with new technology, new market opportunities and so on and, in spite of boardroom opposition, the CE has tried over the past few years to encourage a younger age structure among these senior managers via an active promotion and recruitment policy. Data has been provided on the age structure of these senior managers in 1990. The group had a mean age of 53 years. A sample of 20 senior managers this year finds an average age of 46, standard deviation 4.6 years. Can the CE conclude that his policies have had an effect in terms of reducing the mean age of senior managers?