Answer:
a) margin of error ME = 5.77
b) Margin of error becomes smaller
Step-by-step explanation:
Confidence interval can be defined as a range of values so defined that there is a specified probability that the value of a parameter lies within it.
The confidence interval of a statistical data can be written as.
x+/-zr/√n
x+/-ME
Where margin of error ME = zr/√n
a)
Given that;
Mean = x
Standard deviation r = 25
Number of samples n = 72
Confidence interval = 95%
z(at 95% confidence) = 1.96
Substituting the values we have;
ME = 1.96(25/√72)
ME = 1.96(2.946278254943)
ME = 5.774705379690
ME = 5.77
b)
For n = 89
ME = 1.96(25/√89)
ME = 1.96(2.649994700015)
ME = 5.193989612031
ME = 5.19
5.19 is smaller than 5.77 in a) above. So,
Margin of error becomes smaller
Answer:
The height of the water = 6.2 in. to the nearest tenth
Step-by-step explanation:
∵ The rate of flows of water into the tank = 8000 in.³/min.
∴ The volume of the water in the tank after 10 min. = 8000 × 10 = 80000 in.³
∵ The water take the shape of the tank
∴ The height of the water = volume of water ÷ Area of the base of the tank
∵ The tank is cylinder with diameter 128 in. and height 72 in.
∴ The area of the base of the tank = π(128/2)²
∴ The height of the water = 
∴ The height of the water = 6.2 in. to the nearest tenth
