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there are 600 poetry books at the library.Of the poetry books,8.5 are for children.How many poetry books at the library are for children

We the best reason behind why we call National halothane study is an observational study rather than an experiment is: " In order to be an experiment, the treatments (choice of anesthetic) would have to be randomly assigned." So, option( b) is right one.

We have data from the National Halothane Study that correlates with important research into the safety of anesthetics used in surgery. The above shows the death rate and aesthetic. There is a relationship between the anesthetic used and the death of the patient. The data was collected after that the anesthesia was administered is started. In the observational study, interesting observer in the subjects & any treatment that the subjects recive are beyond the council of the investigators. Here the motion of anaesthesia is anesthetics used her determined by the doctors and the investigators are simply observing. So, it is an observational study due to because in order to be an experiment, the treatments (choice of anesthetic) would have to be randomly assigned. Instead, a patient's anesthetic is selected by his or her doctor(s).

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Complete question:

The National Halothane Study was a major investigation of the safety of anesthetics used in surgery. Records of over 850,000 operations performed in 34 major hospitals showed the following death rates for four common anesthetics:27 Anesthetic A Death rate B CD 1.7% 1.7% 3.4% 1.9% There is a clear association between the anesthetic used and the death rate of patients. Anesthetic C appears dangerous.

a) in order to be an experiment, the subjects would have to be randomly selected from the population. however, these are hospital patients who all have some disease or condition and have not been randomly selected from the population, which includes both healthy and sick people.

b) in order to be an experiment, the treatments (choice of anesthetic) would have to be randomly assigned. instead, a patient's anesthetic is selected by his or her doctor(s).

c) there is not enough information to say for sure, but it is safer to assume that it is only an observational study, so that we are not overconfident about the results.

d) actually, it is an experiment and not an observational study.

There are 173 kinda-prime positive integer less than 1000.

To find the number of kinda-prime positive integer less than 1000, we'll follow these steps:

1. Understand the definition of a kinda-prime number: A positive integer is kinda-prime if it has a prime number of positive integer divisors.
2. Determine the number of prime numbers less than 1000: There are 168 prime numbers less than 1000, as given.
3. Determine the possible prime number of divisors: Since 168 is not too large, we only need to consider 2 and 3 as possible prime numbers of divisors for a kinda-prime number.
4. Analyze the cases:

Case 1: Kinda-prime numbers with 2 divisors (prime numbers)
All prime numbers have exactly 2 divisors (1 and itself). Thus, all 168 prime numbers less than 1000 are kinda-prime.

Case 2: Kinda-prime numbers with 3 divisors
Let N be a kinda-prime number with 3 divisors. Then, N = p^2 for some prime number p. To find the suitable prime numbers p, we need[tex]p^2 < 1000[/tex]. The prime numbers that meet this condition are 2, 3, 5, 7, and 11 (since 13^2 = 169 > 1000). Therefore, there are 5 additional kinda-prime numbers ([tex]2^2, 3^2, 5^2, 7^2, and 11^2[/tex]).

5. Add the total number of kinda-prime numbers from both cases: 168 + 5 = 173.

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[tex]$(\pi(1000)-1)+11=\boxed{177}$[/tex] "kind a-prime" positive integers less than $1000$.

Let [tex]$n$[/tex] be a positive integer with[tex]$k$[/tex] positive integer divisors.

If [tex]$k$[/tex] is prime, then.

[tex]$n$[/tex] is a "kind a-prime" integer.

[tex]$k$[/tex] must be of the form.

[tex]$k=p$[/tex] or [tex]$k=p^2$[/tex] for some prime [tex]$p$[/tex].

If [tex]$k=p$[/tex], then [tex]$n$[/tex] must be of the form.

[tex]$p^{p-1}$[/tex] for some prime [tex]$p$[/tex]. Since [tex]$p < 1000$[/tex], there are.

[tex]$\pi(1000)$[/tex]possible values of [tex]$p$[/tex].

[tex]$p=2$[/tex] gives [tex]$2^1$[/tex], which is not prime, so we have to subtract.

[tex]$1$[/tex] from [tex]$\pi(1000)$[/tex] to get the number of possible.

[tex]$p$[/tex].

[tex]$\pi(1000)-1$[/tex] values of [tex]$p$[/tex] that give a "kind a-prime" integer of this form.

If [tex]$k=p^2$[/tex], then [tex]$n$[/tex] must be of the form.

[tex]$p^{p^2-1}$[/tex] for some prime[tex]$p$[/tex].

There are.

[tex]$\pi(31)=11$[/tex] primes less than [tex]$31$[/tex], and each of them gives a different "kind a-prime" integer of this form.

Since [tex]$31^5 > 1000$[/tex], no primes larger than [tex]$31$[/tex]can be used to form a "kind a-prime" integer of this form.

[tex]$11$[/tex] possible values of [tex]$p$[/tex] that give a "kind a-prime" integer of this form.

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The area of the cement part is 24 m².

Area is the region bounded by a plane shape.

To calculate the area of the part with cement. we use the formula below

Formula:

Where:

From the question,

Given:

Substitute these values into equation 1

Hence, the area is 24 m².

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If the area of the base is 19. 6 ft^2 and the height of the pyramid is 11. 6 ft, the volume of the pyramid is approximately 79.1 cubic feet.

The formula for the volume of a pyramid is given by:

V = (1/3) × base area × height

In this case, we are given that the pyramid has a square base, so the base area is simply the area of a square with side length s:

base area = s^2 = 19.6 ft^2

We are also given the height of the pyramid:

height = 11.6 ft

Substituting these values into the formula for the volume of a pyramid, we get:

V = (1/3) × base area × height

= (1/3) × 19.6 ft^2 × 11.6 ft

≈ 79.1 ft^3 (rounded to the nearest tenth)

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Answer:

I would say convenience sampling. It's hard to tell. Sampling every other person is like systematic sampling, BUT convenience sampling would be to sample people that are easy to reach.

The major flaw of the linear probability model is, Option d, which allows predicted values to range from above 1 to below 0

The binary dependent variable, which accepts values of 0 and 1, and the independent variables are assumed to have a linear relationship under the linear probability model.

The anticipated values from the linear probability model, however, can range from 0 to 1, and in some circumstances, they can be either above or below 0. This goes against the dependent variable's probabilistic character and can produce inaccurate forecasts.

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In the given equation r = 2/5 t "r" is the dependent variable.

In mathematics, a variable is a symbol that represents a quantity that can take on different values. In many cases, variables can be divided into two types: dependent variables and independent variables.

An independent variable is a variable that can be changed freely, and its value is not dependent on any other variable in the equation.

A dependent variable is a variable whose value depends on the value of one or more other variables in the equation

Here we have

Lin notices that the number of cups of red paint is always  2/5 of the total number of cups.

She writes the equation r = 2/5 t to describe the relationship.

In the equation, r = 2/5 t, "t" represents the total number of cups, while "r" represents the number of cups of red paint.

Here "t" is the independent variable because it represents the total number of cups, which can be changed arbitrarily.

The value of "r" depends on the value of "t" because the number of cups of red paint is always 2/5 of the total number of cups.

Therefore,

In the given equation r = 2/5 t "r" is the dependent variable.

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Complete Question:

Lin notices that the number of cups of red paint is always  2/5 of the total number of cups. She writes the equation r = 2/5 t to describe the relationship. Which is the independent variable? Which is the dependent variable? Explain how you know.

The best prediction possible for the number of times the spinner will land on green or blue is given as follows:

30 spins.

A probability is calculated as the division of the desired number of outcomes by the total number of outcomes in the context of a problem/experiment.

Out of six regions, three are green and two are blue, hence the probability of one spin resulting in green or blue is given as follows:

p = (3 + 2)/6

p = 5/6.

Thus the expected number out of 36 trials of spins resulting in green or blue is given as follows:

E(X) = 5/6 x 36

E(X) = 30 spins.

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The tax on the belt buckle is $1.56

What is Rate?

In general terms, a rate is a measure of the relationship between two quantities that are measured in different units. A rate expresses how much of one thing there is per unit of another thing. For example, miles per hour is a rate that expresses how many miles are traveled in one hour.

To calculate the tax on the belt buckle, we need to multiply the price of the belt buckle by the sales tax rate:

Tax = Price x Tax rate

In this case, the price of the belt buckle is $25 and the sales tax rate is 6.25%. To convert the tax rate from a percentage to a decimal, we need to divide it by 100:

Tax rate = 6.25% ÷ 100 = 0.0625

Now we can calculate the tax on the belt buckle:

Tax = Price x Tax rate

= $25 x 0.0625

= $1.56

Therefore, the tax on the belt buckle is $1.56. The total cost of the belt buckle including tax would be $25 + $1.56 = $26.56.

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The distance of the object from the helicopter is 698 ft.

Distance is the length between two points.

To calculate how far the object is above the helicopter, we use the formula below.

Formula:

Where:

From the question,

Given:

Substitute these values into equation 1 and solve for H

Hence, the distance is 698 ft.

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It has been proved that the lines MN and PR are parallel because they have the same slope.

We are given the coordinates of the points P, Q and R as:

P(-3, -6)

Q(1, 4)

R(5, -2)

Since M is the midpoint of PQ, we have:

M = (-3 + 1)/2, (-6 + 4)/2

M = (-1, -1)

N is the midpoint of QR and so:

N = (1 + 5)/2, (4 - 2)/2

N = (3, 1)

Slope of MN = (1 + 1)/(3 + 1) = 1/2

Slope of PR = (-2 + 6)/(5 + 3)

Slope of QR = 4/8 = 1/2

Both slopes are equal and as such they are parallel lines

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The measure of angle A and angle B are 28.61 and 61.39 rounded to two decimal place, using trigonometric ratio of tangent for the respective angles.

The trigonometric ratios is concerned with the relationship of an angle of a right-angled triangle to ratios of two side lengths.

The basic trigonometric ratios includes;

sine, cosine and tangent.

tan B = 6/11 {opposite/adjacent}

B= tan⁻¹(6/11) {cross multiplication}

B = 28.6105.

tan A = 11/6 {opposite/adjacent}

A= tan⁻¹(11/6) {cross multiplication}

A = 61.3895.

Therefore, the measure of angles A and B are 28.61 and 61.39 rounded to two decimal place, using trigonometric ratio of tangent for the respective angles.

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The chance/

probability

is

16/33

, or roughly 0.485 that 1 and 2 are in the

same set.

Let's say we divide the range of numbers from

1 to 15

into two sets, each containing seven and eight numbers, respectively. Finding the likelihood that the numbers 1 and 2 are included in the same

set

is our goal.

We can determine the

total number

of ways to divide the numbers into the two sets of

7

and

8

in order to begin solving this issue. Calculating this yields the result 6435 using a formula.

The number of ways in which the pairs 1 and 2 can be found in the same set must then be determined. Considering that there are

seven numbers

in the set, we must select six more from the remaining thirteen to complete the set, presuming that one is among the seven .There are

1716

ways to do this. The number of methods remains the same, 1716, even if we suppose that 2 is among the set of 7 numbers.

Hence, there are

3432

different ways to combine the numbers 1 and 2 into one set. The chance is 16/33, or roughly 0.485, when we divide this number by the total number of possible

divisions

of the numbers.

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Answer:

Using similar triangles, we can set up a proportion:

(tree height)/(tree shadow) = (building height)/(building shadow)

Plugging in the given values, we get:

8/4 = 24/x

Solving for x, we get:

x = (24 x 4)/8 = 12 feet

Therefore, the length of the building's shadow is B. 12 feet.

Step-by-step explanation:

vf = vo + at      vo = 0 in this case  ( you dropped it from 'at rest')

4 f/s = 32 t

t = 1/8 s

df = do + vot + 1/2 at^2                  df = final position = 0 ft (on the ground)

0 = do  + 0   + 1/2 (-32)(1/8)^2

   solve for do = 1/4 foot

Let x be the length of the pen and y be the width of the pen.

The total cost of the pen is given by:

Cost = 3x + 5y = 300

3x + 5y = 300

3x = 300 - 5y

x = (300 - 5y)/3

The area of the pen is given by:

Area = xy = (300 - 5y)/3 * y

A reasonable prediction for the number of times a sixth or seventh grader will be chosen is 24 out of the 40 games.

What is reasonable prediction?

A reasonable prediction is a prediction made with a reasonable degree of accuracy or likelihood, based on available information and knowledge. It is based on facts, past events, and logical assumptions, and is not based on conjecture or guesswork. Reasonable predictions can be made about future events, trends, and outcomes, and can be used to inform decisions, plans, and strategies.

The total number of sixth and seventh graders on the team is:

10 sixth graders + 14 seventh graders = 24 students

The total number of students on the team is:

10 sixth graders + 14 seventh graders + 16 eighth graders = 40 students

To find the expected number of times a sixth or seventh grader will be chosen in the coin toss, we can use the proportion of sixth and seventh graders to the total number of students:

(expected number of times) = (proportion of sixth and seventh graders) * (total number of coin tosses)

(expected number of times) = (24/40) * 40

(expected number of times) = 24

Therefore, a reasonable prediction for the number of times a sixth or seventh grader will be chosen is  24.

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The amount that each charity gets is $25.

The charity raise simply define as we raise funds in the form of small amounts of money from a huge crowd of people within a specific period of time.

For example, if 100 people donate $50 each to your crowdfunding campaign in two weeks, you will be able to raise $5000.

To find the amount that each charity got, we have to divide the total charity amount raised in the proportion given, i.e., 1/6.

Each charity gets 1/6 of the total amount raised, which is $150.

So, we need to divide $150 by 6:

$150 ÷ 6 = $25

Therefore, each charity received $25.

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The expression that represents the total amount that Julian paid at the register in terms of x is 0.84x.

What is Percentage?

Percentage is a way of expressing a proportion or fraction as a quantity out of 100. The word "percent" means "per hundred," so percentages are often denoted by the symbol %, which represents one part in a hundred.

The first step is to find the discounted price after the 20% discount. This can be found by multiplying the original price by (1 - 0.2), which represents a 20% reduction.

Discounted price = x - 0.2x = 0.8x

Next, a 4% tax is added to the discounted price. This can be found by multiplying the discounted price by (1 + 0.04), which represents a 4% increase.

Total amount paid = (0.8x) * (1 + 0.04) = 0.84x

Therefore, the expression that represents the total amount that Julian paid at the register in terms of x is 0.84x.

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Answer: positive 2

Step-by-step explanation:

The best prediction possible for the number of times the spinner will not land on yellow is 18.

What is probability?

Probability is a measure of the likelihood of an event occurring. It is a number between 0 and 1, where 0 means the event is impossible and 1 means the event is certain to happen.

Assuming that the spinner is fair and all outcomes are equally likely, we can calculate the probability of the spinner not landing on yellow in one spin by adding up the probabilities of all other outcomes, which are green, blue, and red.

The probability of the spinner not landing on yellow in one spin is:

P(not yellow) = P(green) + P(blue) + P(red)

= 1/6 + 1/3 + 1/6

= 1/2

Therefore, the expected number of times the spinner will not land on yellow in 36 spins is:

E(not yellow) = 36 x P(not yellow)

= 36 x 1/2

= 18

So the best prediction possible for the number of times the spinner will not land on yellow is 18. However, it's important to note that this is just a prediction based on probabilities, and the actual number of times the spinner doesn't land on yellow in 36 spins may vary.

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Assuming a two-tailed test with 9 degrees of freedom (10 stores minus 1), the p-value for a t-value of 2.3 is approximately 0.040.

In order to calculate the p-value, we need to know the specific test being used and the significance level of the test. Let's assume that the test is a two-tailed t-test with a significance level of 0.05.

Since the test statistic is 2.3, we need to find the probability of getting a t-value of 2.3 or greater (in absolute value) under the null hypothesis. We can use a t-distribution table or a statistical software to find the corresponding p-value.

Assuming a two-tailed test with 9 degrees of freedom (10 stores minus 1), the p-value for a t-value of 2.3 is approximately 0.040. Therefore, if the significance level of the test is 0.05, we would reject the null hypothesis and conclude that there is a significant difference between the ratings given by the three reviewers.

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In the circle the mesaure of ∠ACF is  7

The distance from the centre of a circle to any point on the boundary is called the radius. The radius is half of the diameter; 2r=d 2 r = d . The line segment that joins two points on the circle is a chord.

If diameter of a circle bisects a chord ,then it must be perpendicular to the chord.

∴ m∠ACF = 90°  

(8x + 34)° = 90°

8x = 90 - 34

x = 56/8

x = 7

Hence,mesaure of ∠ACF = 7

Complete question : In Circle C, the diameter AB bisects the chord EF.

If m∠ACF = (8x+34)°, enter in the correct value of x.

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Answer: 14%

Step-by-step explanation:

Our formula is i=prt but we're trying to find the rate (r) so we'll rearrange it to become r=i/pt.

i = $245

p = $7000

t = 3/12= 0.25 years

[tex]r=\frac{245}{(7000)(0.25)} \\r = 0.14[/tex]

The depreciation rate of Nancy is 15%.

Depreciation is the reduction in the value of an asset over time due to wear and tear, obsolescence, or other factors. It is a non-cash expense that is recorded on a company's income statement, which reflects the decrease in the asset's value during its useful life. Depreciation is commonly used in accounting to allocate the cost of an asset over its useful life, and it helps businesses to accurately reflect the true value of their assets on their financial statements.

In mathematics, a function is a relation between a set of inputs and a set of possible outputs with the property that each input is related to exactly one output.

The given function V(t) = [tex](30000*0.85)^{t}[/tex]represents the value of Nancy's car after t years.

Depreciation rate is the rate at which the value of an asset decreases over time. In this case, the depreciation rate of Nancy's car is 1 - 0.85 = 0.15 or 15%.

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Answer:

use desmos graphing calculator it helps alot

Step-by-step explanation:

x^{2}-x-6=0 has two zeros/solutions

x^{2}-x-6=0 has 1 zero/solution

x^{2}-x-6=0 has no zero/solution

The diameter of the circle is √74. Answer: C.

What is circle?

A circle is a geometric shape that consists of all points in a plane that are equidistant from a fixed point called the center. It can also be defined as the set of points that are a fixed distance (called the radius) away from the center point.

To find the diameter of the circle, we need to find the distance between points A and B, which will give us the length of the diameter.

Using the distance formula, we have:

d = √[(x2 - x1)² + (y2 - y1)²]

where (x1, y1) = (-3, 6) and (x2, y2) = (-8, -1).

Plugging in the values, we get:

d = √[(-8 - (-3))² + (-1 - 6)²]

= √[(-5)² + (-7)²]

= √[25 + 49]

= √74

Therefore, the diameter of the circle is √74. Answer: C.

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Answer:

  2

Step-by-step explanation:

You want the average rate of change of f(x) = -x² -2x +6 on the interval [-7, 3].

The average rate of change of f(x) on the interval [a, b] is computed as ...

  m = (f(b) -f(a))/(b -a)

For the given function f(x), this is ...

  m = (f(3) -f(-7))/(3 -(-7)) = (-9 -(-29))/10 = 20/10 = 2

The average rate of change of f(x) on the interval [-7, 3] is 2.

__

Additional comment

The derivative of the function is f'(x) = -2x -2. The midpoint of the interval is x = (-7 +3)/2 = -2. The value of the derivative at the midpoint is equal to the average rate of change on the interval:

  -2(-2) -2 = 4 -2 = 2 . . . . average slope between x=-7 and x=3.

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Answer:

-23. In my explanation I will include in my picture how this will look in your final answer

Step-by-step explanation:

So to solve this, I first set x + 3 = 0. This means that x = -3, which we will use soon. Now, here's how you would work out this problem. It would be confusing if I explained over text, so I included a picture of my work.

You would first set up your problem like it is in the picture. Then, bring 2 down. Next, multiply 2 by -3 (for future problems, you would multiply the number you brought down by whatever number is on the side). -3 × 2 = -6, so you would put that under 3 (as shown in the picture). Now, add 3 and -6 (which = -3). Repeat this step each time.

I hope this made sense! Please let me know if you have any questions.