In: Math
a) H0: > 10.2
H1: < 10.2
The test statistic t = ()/(s/)
= (8.7 - 10.2)/(0.52/)
= -23.26
At alpha = 0.05, the critical value is t0.05, 64 = -1.669
Since the test statistic value is less than the critical value (-23.26 < -1.669), so we should reject the null hypothesis.
Yes, at 0.05 significance level we can conclude that growth-areas planners significantly less experienced than the metropolitan average.
b) H0: < 23899
H1: > 23899
The test statistic t = ()/(s/)
= (25665 - 23899)/(722/)
= 19.72
At alpha = 0.05, the critical value is t0.95, 64 = 1.669
Since the test statistic value is greater than the critical value (19.72 > 1.669), so we should reject the null hypothesis.
At 0.05 significance level there is sufficient evidence to conclude that growth area planners salaries are significantly higher than Melbourne overall.