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3 years ago

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

μ=72, σ=2

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%

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:

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.

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.

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.