A union leader in the Maritime Workers' Union believed that workers at the Port of Brisbane were receiving a lower weekly salary than workers at Port...

A union leader in the Maritime Workers' Union believed that workers at the Port of Brisbane were receiving a lower weekly salary than workers at Port Kembla. To determine whether this claim was valid, they took samples of size 15 and 18 in Brisbane and Port Kembla, respectively, and found that the average and standard deviation of the weekly salaries were $845.43 and $65.72 respectively in Port Kembla, and $806.19 and $59.13 in Brisbane. Use Brisbane minus Port Kembla, and answer correct to two decimal places.