Confidence Intervals question
1. 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 16 and 14 in Brisbane and Port Kembla, respectively, and found that the average and standard deviation of the weekly salaries were $894.15 and $61.42 respectively in Port Kembla, and $859.17 and $66.28 in Brisbane. Use Brisbane minus Port Kembla, and answer correct to two decimal places.
a). Determine a point estimate for the difference in the average weekly salary between the two ports.
b). Calculate the standard error for the difference between sample means assuming that the workers' salaries in both locations are normally distributed and have the same population variance.
c). Use Kaddstat to determine a 99% confidence interval for the difference between the mean weekly salaries in Brisbane and Port Kembla. lower limit