Answer:
a) The 99% confidence interval for the mean noise level = [122.44, 151.96]
b) Sample standard deviation, s = 17.3dB
Explanation:
Noise levels at 5 airports = 147,123,119,161,136
Mean noise level
Variance of noise level
Standard deviation,
a) Confidence interval is given by
For 99% confidence interval Z = 2.576,
Number of noises, n = 5
Substituting
The 99% confidence interval for the mean noise level = [122.44, 151.96]
b) Sample standard deviation
Sample standard deviation, s = 17.3dB
Explanation:
It took for the sound to reach the 1st wall and at the same time time, the same sound took to reach the 2nd wall. Assuming that the sound travels at 343 m/s, then let be the distance of the person to the 1st wall and be the distance to the 2nd wall. So the distance between the walls X is
I think it is d. I think but I don't know for a fact.