Answer:
The 95% confidence interval for the proportion of students who get coaching on the SAT is (0.1232, 0.147).
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of 
, and a confidence level of 
, we have the following confidence interval of proportions.
In which
z is the z-score that has a p-value of 
.
427 had paid for coaching courses and the remaining 2733 had not.
This means that 
95% confidence level
So 
, z is the value of Z that has a p-value of 
, so 
.
The lower limit of this interval is:
The upper limit of this interval is:
The 95% confidence interval for the proportion of students who get coaching on the SAT is (0.1232, 0.147).
Answer:
The height of the tank is 0.5 yards.
Step-by-step explanation:
To determine what is the height, in yards, of a cylindrical water tank that holds 1,884 cubic yards of water and has a diameter of 120 feet, knowing that the volume of a cylinder is equal to pi multiplied by the radius squared, multiplied by the height, the following calculation must be done:
1 foot = 0.3333 yards
R = Diameter / 2
R = 120/2 = 60
3.14 x 60 ^ 2 x H = 1,884
3.14 x 3,600 x H = 1,884
3.14 x 1,200 x H = 1,884
3.768 x H = 1.884
H = 1,884 / 3,768
H = 0.5
Therefore, the height of the tank is 0.5 yards.
Answer:
-3.45+5.1=1.65
Step-by-step explanation:
You could use a calculator (just sayin)
Let
x------> the length side of the square base of the box
y-------> the height of the box
we know that
volume of the box=b²*h
b=x
h=y
volume=256 cm³
so
256=x²*y------>y=256/x²--------> equation 1
<span>The amount of material used is directly proportional to the surface area, so we will minimize the amount of material by minimizing the surface area.</span>
surface area of the cardboard=area of the base+perimeter of base*height
area of the base=x²
perimeter of the base=4*x
height=y
surface area=x²+4x*y-----> equation 2
substitute equation 1 in equation 2
SA=x²+4x*[256/x²]-----> SA=x²+1024/x
step 1
find the first derivative of SA and equate to zero
2x+1024*(-1)/x²=0------> 2x=1024/x²----> x³=512--------> x=8 cm
y=256/x²------> y=256/8²-----> y=4 cm
the answer is
the length side of the square base of the box is 8 cm
the height of the box is 4 cm
