The mean noise level of 22 randomly selected areas designated as emergency rooms was 68.9 dBA and the sample standard deviation is 5.21 dBA. The mean noise level for 20 randomly selected areas designated as operating theaters was 53.3 dBA and the sample standard deviation was 6.73 dBA. An engineer reported a confidence interval of (3.6542, 10.7253) for the difference in the mean noise level between areas designated as emergency rooms and areas designated for operating theaters, but neglected to specify the significance level. Estimate the significance level of the confidence interval if the population standard deviations, 1 and oz of the two populations are unknown but equal. At the estimated significance level, could it be concluded that on average, the emergency rooms are noisier than the operating theaters by a minimum of 4 dbA