Urban planners in Melbourne average 10.2 years’ experience

Urban planners in Melbourne average 10.2 years’ experience. We know this from a Census of urban planners, but the raw data was lost, so we cannot use the data to compute σ. What an inconvenience!    (a) In a random sample of 65 urban planners in Melbourne’s growth areas, the average was 8.7 years with a standard deviation of 0.52. Are growth-areas planners significantly less experienced than the metropolitan average? Presume alpha = 0.05 (b) The same sample of urban planners reports an annual salary of $25,665 with s=$722. The statewide average salary is $23,899. Is there statistical evidence to suggest that growth area planners salaries are significantly higher than Melbourne overall? Presume alpha = 0.05