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
Answer: D.) 3hrs
Explanation:
Given the following :
A boat can move at a constant velocity of 8 km/h; How long will it take for the boat to move 24 km
Recall:
Velocity = Displacement / time
For the boat to travel a distance of 24 km at a constant velocity of 8km /hr
Time taken = Displacement(distance moved) / velocity
Time taken = 24km / 8kmhr^-1
Tine taken = 3hrs
Answer:
v = 12.86 km/h
v = 3.6 m/s
Explanation:
Given,
The distance, d = 13.5 km
The time, t = 21/20 h
= 1.05 h
The velocity of a body is defined as the distance traveled by the time taken.
v = d / t
= 13.5 km / 1.05 h
= 12.86 km/h
The conversion of km/h to m/s
1 km/h = 0.28 m/s
12.86 km/h = 12.86 x 0.28 m/s
= 3.6 m/s
Hence, the velocity in m/s is, v = 3.6 m/s
Answer:
Option B, to establish the reference polarity for induced voltages
Explanation:
Dot basically indicates the polarity of the electrical windings. Currents entering and leaving the same dotted ends will produce magnetic flux in same direction while the current entering at one dotted end and leaving at another dotted end will produce opposing magnetic flux.
Thus it is clear that dot represents the terminals having same phases of induced AC voltages so that only one winding is loaded at a time.
Hence, option B is correct