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jenyasd209 [6]
2 years ago
13

A 95% confidence interval is (70,110). what is the margin for error? A. 19 B.38 C.20 D.40

Mathematics
1 answer:
goldfiish [28.3K]2 years ago
3 0

Answer:

C.20

Step-by-step explanation:

Confidence interval concepts:

A confidence interval has two bounds, a lower bound and an upper bound.

A confidence interval is symmetric, which means that the point estimate used is the mid point between these two bounds, that is, the mean of the two bounds.

The margin of error is the difference between the two bounds, divided by 2.

In this question:

Lower bound: 70

Upper bounf: 110

Margin of error:

M = \frac{110 - 70}{2} = \frac{40}{2} = 20

Thus the correct answer is given by option C.

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Consider this cube with a volume of 64 cubic centimeters.
Eduardwww [97]

Answer:

This is a perfect cube.

The side length is 4.

Taking the cube root of the volume will determine the side length.

Step-by-step explanation:

We are told that:

A cube has volume 64 centimeters cubed.

The formula for the volume of a cube = s³

Where s = side length

Hence

64 cm³ = s³

We can find s by finding the cube root of both sides

Hence,

cube root(64) = cube root(s³)

s = 4 cm

Note that 64 is a perfect cube because 4 × 4 × 4 = 4³ = 64 cm³

Therefore, it can be concluded of the cube that:

This is a perfect cube.

The side length is 4.

Taking the cube root of the volume will determine the side length.

3 0
2 years ago
Which number replaces the box to make this a true number sentence? 4 × (8 – 5) = (4 × 8) – ( × 5) A. 4 B. 5 C. 12 D. 32
Andre45 [30]
The answer is A: 4. This is easy once you know the order of operations, aka PEMDAS. Parentheses, exponents, multiplication/division, and addition/subtraction.
3 0
3 years ago
Please help im really confused :(​
pantera1 [17]

Answer:

a) π

b) 33.4

Step-by-step explanation:

C = πd

1) substitute 105 for C: 105 = πd

2) plug in approximate value of 3.14 for π: 105 = (3.14) d

3) isolate to solve for d: 105/3.14 = d

4) simplify: 105/3.14 ≈ 33.4

5 0
3 years ago
The elevation E, in meters, above sea level at which the boiling point of a certain liquid is t degrees Celsius is given by the
Anna007 [38]

Answer:

E(119.5)= 730m

Step-by-step explanation:

Given

E(t)= 1200(120-t)+520(120-t)^2

Required

Determine E(119.5)

E(t)= 1200(120-t)+520(120-t)^2

Simply substitute 119.5 for t

E(119.5)= 1200(120-119.5)+520(120-119.5)^2

Evaluate the expressions in bracket

E(119.5)= 1200(0.5)+520(0.5)^2

Solve 0.5²

E(119.5)= 1200 * 0.5+520*0.25

E(119.5)= 600+130

E(119.5)= 730

Hence;

E(119.5)= 730m

5 0
3 years ago
What are the roots of the polynomial equation x3-7x=6x-12?
Ilia_Sergeevich [38]
This is not a polynomial equation unless one of those is squared.  As it stands x=-.833.  If you can tell me which is squared I can help solve the polynomial.

Ok, that is usually notated as x^3 to be clear.   I'll solve it now.

x^3-13x-12=0

Then use factor theorum to solve x^3-13x-12/x+1 =0
So you get one solution of x+1=0
x=-1

Then you have x^2-x-12 now you complete the square.

Take half of the x-term coefficient and square it. Add this value to both sides. In this example we have:

The x-term coefficient = −1

The half of the x-term coefficient = −1/2

After squaring we have (−1/2)2=1/4

When we add 1/4 to both sides we have:

x2−x+1/4=12+1/4

STEP 3: Simplify right side

x2−x+1/4=49/4

STEP 4: Write the perfect square on the left.

<span>(x−1/2)2=<span>49/4
</span></span>

STEP 5: Take the square root of both sides.

x−1/2=±√49/4

STEP 6: Solve for x.

<span>x=1/2±</span>√49/4

that is,

<span>x1=−3</span>

<span>x2=4</span>

<span>and the one from before </span>

<span>x=-1</span>

7 0
3 years ago
Read 2 more answers
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