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vfiekz [6]
3 years ago
5

I can’t figure this out at all, please help me!

Mathematics
1 answer:
Sidana [21]3 years ago
8 0

The Bell Curve aka Normal Distribution aka Gaussian is important stuff that everybody functioning in modern society should understand at least up to the 68-95-99.7 rule.

A normal distribution is characterized by a mean μ and a standard deviation σ.  The distribution has the characteristic bell shape, with the center of the bell at x=μ.  

The value of σ says how wide the bell is.  That's where the 68-95-99.7 rule comes in.  The first value, 68, means that 68% of the area of the bell curve is   contained in plus or minus one standard deviation.  That means there's a 68% chance a random x drawn from this distribution is between μ-σ and μ+σ.

The 95 means that 95% of the area of the bell within two standard deviations of the mean.  A random x has a 95% chance of being between μ-2σ and μ+2σ.

It's the same story for 99.7% except that encompasses everything within three standard deviations of the mean.

Now let's answer the question. We have μ=10, σ=1.5.

a.  We want a 95% probability, which we learned is within two standard deviations, two sigma of the mean.   So the lower bound is 10 - 2(1.5) = 7 and the upper bound is 10 + 2(1.5) = 13.

Answer: 7 to 13

b.  We're asked for 68%; we know that's one sigma, from 10-1.5 to 10+1.5.

Answer: 8.5 to 11.5

4.

μ=72, σ=2

a.

We want P(x < 68)

In general to do these sorts of problems we convert our x test on the particular normal distribution given to a z test on a standard normal distribution with mean zero and standard deviation one.

z = (x - μ)/σ = (68 - 72)/2 = -2

We're interested in P(z < -2), i.e. the probability we landed more than two standard deviations below the mean.  The 68-95-99.7 rules says 95% is between plus or minus two sigma, which leaves 5%, split equally between being less than minus two sigma and more than plus two sigma.

Answer: 2.5%

b.

I forgot to answer part b.  Here we go.

Between 70 and 72 inches is between -1 standard deviation below the mean and the mean.  So we want the area of the bell curve between z=-1 and z=0.   That's half of the 68% that we get when we go from z=-1 to z=1.

Answer: 34%

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Which statement about the equation 3/4y = 5/x is true?
VARVARA [1.3K]

Answer:

the answer would be no solution

Step-by-step explanation:

because, Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation

  3/4y-(5/x)=0

and from there you may not do anything else.

3 0
3 years ago
Answer questions 15 and 17 show work pls
fredd [130]

Answer:

#15) B. 30 mn^5

#17) B. 1/2

Step-by-step explanation:

<h2>#15:</h2>

The area of a trapezoid is given in the formula: 1/2(a + b) * h, where a is the length of the top of the trapezoid, b is the length of the bottom of the trapezoid, and h is the height of the trapezoid.

All of these measurements are given so all that you need to do is to substitute these values into the formula.

Substitute 3 for a, 9 for b, and 5 for h.

  • 1/2(3 + 9) * 5

Solve inside the parentheses first. Add 3 and 9.

  • 1/2(12) * 5

Multiply 12 and 1/2 together.

  • 6 * 5

Multiply 6 and 5.

  • 30

We need to figure out if the area is to the 5th or 6th power. When we added 3 and 9 together, we combined like terms so the exponent stayed to the 3rd power.

After multiplying this ^3 by the 5mn^2, the exponent becomes to the 5th power because you add exponents when multiplying.

Therefore the final answer is B. 30 mn^5.

<h2>#17:</h2>

When going down from 32 to 8 to 2, you can see that each number is being divided by 4.

32 / 4 = 8...

8 / 4 = 2...

So to find the next number in this sequence you would divide 2 by 4.

  • 2 / 4 = 1/2

The answer is B. 1/2.

6 0
3 years ago
Complete the Table
lianna [129]

Answer:

a= 6

b = 7

c = 8

d = 7

e = 6

Step-by-step explanation:

Notice that the bike is 6 feet above the ground to start with, so when it starts rolling, the green dot is exactly 6 feet from the ground, which gives a=6

when the distance covered by the bike is \frac{\pi}{2}, (see first red dot in the attached image), the position of the green dot is exactly 1 foot added to 6 ft= 7 feet

so b = 7

when the distance covered is \pi, now the green dot would be at the top of the wheel (second red dot in the attached image) which involves adding 2 feet to the original 6 feet. That is: c = 8

when the distance covered is \frac{3\pi}{2}, the green dot is at the position of the third red dot in the attached image., that it exactly one foot added to 6 feet = 7 ft which gives the value of d = 7

and finally, when the distance covered is 2\pi. the green dot has completed a full circle and is now again in its lower position (nothing - zero) added to 6 feet =  6ft, giving e = 6.

5 0
3 years ago
What is the volume of the following rectangular prism?
sergij07 [2.7K]

Answer:

33 cubic unit

Step-by-step explanation:

Volume of the prism = base area * height

                                  = 9 * 3 2/3            {Change improper to proper fraction}

                                  = 9*\frac{11}{3}\\\\= 3* 11\\\\= 33 unit^{3}

8 0
3 years ago
I need help, I don't know how to do it.
Sindrei [870]

Answer:

Step-by-step explanation:

to solve this problem we can use the Pythagorean theorem

UT and TL are the legs, while LU is the hypotenuse

We have to find LU so we can proceed like this

x^2 + (x+1)^2 = LU^2

x^2 + x^2 + 1 + 2x = LU^2

2x^2 + 2x + 1 = LU^2

LU = +/- \sqrt{2x^2+2x+1

we have to take only the positive value because a length can’t be negative.

2x^2 + 2x + 1 is positive for every value of x, so the final answer is

\sqrt{2x^2+2x+1}

5 0
2 years ago
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