For one kindergarten class in his district, a researcher determines which children already can read simple words and which children cannot upon entering kindergarten. The children are followed until third grade, at which point they are tested to determine the grade level at which they are reading. Those children who were reading simple words upon entering kindergarten are found to be reading at a higher level than those who could not read simple words upon entering kindergarten. Fill in the Blank: The researcher _____________________________. Select one: a. can conclude that children should be taught to read in preschool, as there are clear benefits to reading early. b. needs to check the reading level of the children's parents. c. cannot establish a cause-and-effect relationship because the study did not use a random sample of kindergarten students. d. finds these results beneficial, as there may be confounding variables in this study. e. needs to retest in sixth grade or no conclusions can be reached.

Answer: The first and third options are correct.

Step-by-step explanation:

The value of b is degree 104.we can find by using vertically opposite theorem.

Vertical Angles are when two lines intersect each other then the opposite angles formed due to intersection are called vertical angles or vertically opposite angles. A pair of vertically opposite angles are always equal to each other.The point where they meet is called a vertex.

Vertical opposite angles that are opposite each other when two lines cross are also known as vertical angles because the two angles share the same corner. Opposite angles are also congruent angles meaning they are equal or have the same measurement.

Now we have

(b-308)=(-2b+4)

b+2b=4+308

3b=312

b=104

Hence the value of b is 104 degree.

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The lower left-hand corner of the graph is the third quadrant.

It contains the negative values of both x and y.

Quadrant

The axes of a two-dimensional Cartesian system divide the plane into four infinite regions called quadrants, each bounded by two half-axes.

Cartesian system

A Cartesian coordinate system in a plane is a coordinate system that specifies each point uniquely by a pair of numerical coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, measured in the same unit of length.

coordinates

Coordinates are numbers which determine the position of a point or a shape in a particular space.

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Answer:

150 of 400 can be written as:

150400To find percentage, we need to find an equivalent fraction with denominator 100. Multiply both numerator & denominator by 100

150400 × 100100= (150 × 100400) × 1100 = 37.5100Therefore, the answer is 37.5%

If you are using a calculator, simply enter 150÷400×100 which will give you 37.5 as the answer.

The 4 steps in solving simple problems in mathematics is explained below.

According to the author called Polya created his famous four-step process for problem solving that one is used all over to aid people in problem solving

The first and foremost Step is to understand the problem which includes identification of  the unknowns and figure out what the problem tells you is important and then we have to identify any information that is irrelevant to the problem.

Then the nest step is to Devise a plan which means that Look for a pattern and then by using it we have to make a table, diagram or chart and then write an equation.

Then we have to move onto the next steps that is to carry out the plan which means the process of solving the question.

Then the final step is to Look back problem that is none other than check and interpret its reliability of the solution

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The probability that the sample mean is between 1300 and 1400 is approximately 1.34%.

We can use the Central Limit Theorem and the standard normal distribution to calculate the probability that the sample mean is between 1300 and 1400. The Central Limit Theorem states that as the sample size increases, the distribution of the sample means will approach a normal distribution, regardless of the distribution of the population.

Since we have a sample of 80 observations, we can assume that the sample mean follows a normal distribution with a mean of 1460 (the population mean) and a standard deviation of:

Standard deviation of the sample mean

= population standard deviation ÷ [tex]\sqrt {sample size[/tex]

[tex]= 270 \div \sqrt{80} = 27[/tex]

So the standard deviation of the sample mean is 27.

We can now standardize the interval between 1300 and 1400 by subtracting the mean and dividing it by the standard deviation of the sample mean.

[tex]Z_1[/tex] = (1300 - 1460) / 27 = -2.59

[tex]Z_2[/tex] = (1400 - 1460) / 27 = -2.22

We need to find the area under the standard normal distribution curve between Z1 and Z2.

Using a standard normal table or a calculator with the standard normal distribution function, we can find the probability that a random variable from the standard normal distribution is between -2.59 and -2.22. This probability is approximately 0.0134 or 1.34%.

Therefore, the probability that the sample mean is between 1300 and 1400 is approximately 1.34%.

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41% is the percentage increase of the area of the building pace.

When the denominator is 100, percentages are really just fractions. We place the percent sign (%) next to the number to indicate that the number is a percentage.

Comparing two amounts while rebasing the second amount to 100 is the simplest way to use percentages. The word percentage comes from the Latin term per centum, which means "by the hundred." In the 16th century, the Latin term made its way into English. It was later abbreviated to %.

A company is expanding it building area from 18,000 square feet to 25,380 square feet.

= (25,380 - 18,000)

= 7,380

Now,

= 7,380 / 18,000

= 0.41

the percentage increase of the area of the building pace: 0.41 / 100 = 41%

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To calculate the percent change of two numbers such as 99 to 71, you use the Percent Change Formula, where a is the start value and b is the end value. When we insert a = 99 and b = 71 in the formula above, then we get the following that we can simplify and solve to get the percent change from 99 to 71.

Change ≈ -28.2828%

The theoretical likelihood of selecting a heart is 1/16 times higher than the actual likelihood.

In the given question, we have to find the experimental probability of choosing a heart compare with the theoretical probability of choosing a heart.

We are aware that a deck's total number of cards= 52

Total number of hearts = 13

Then the theoretical probability of getting a heart = Number of cards have hearts/Total cards

Then the theoretical probability of getting a heart = 13/52

Then the theoretical probability of getting a heart = 1/4

Then the theoretical probability of getting a heart = 0.25

Cards chosen by Rochelle : Clubs 29, Spades 13, Hearts 15, Diamonds 23

Total cards  = 80

The experimental likelihood of experiencing a heart attack = Number of cards have hearts/Total cards

The experimental likelihood of experiencing a heart attack = 15/80

The experimental likelihood of experiencing a heart attack = 3/16

The experimental likelihood of experiencing a heart attack = 0.185

Since, 0.25 > 0.1875 so, Theoretical probability > Experimental probability

and,

Theoretical probability = 0.25-0.1875

Theoretical probability = 0.0625

Theoretical probability = 625/10000

Theoretical probability = 1/16

Hence, the theoretical likelihood of selecting a heart is 1/16 times higher than the actual likelihood.

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Tracy got 20 questions correct in her test.

Tracy took a test in which there are 24 questions, out of which Tracy got 5/6 correct.

Hence he got 24 x 5/6 = 20 questions correct.

An equation is a mathematical statement that shows that two mathematical expressions are equal. For instance, 3x + 5 = 14 is an equation, in which 3x + 5 and 14 are two expressions separated by an ‘equal’ sign.

So ,an equation to model this would be:

x = 24 x 5/6

where x is the number of questions tracy answered correctly.

Hence Tracy answered 20 questions correctly.

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In linear equation ,The length of waterslide is 12 yards.

What in mathematics is a linear equation?

A linear equation is a first-order (linear) term plus a constant in the algebraic form y=mx+b, where m is the slope and b is the y-intercept.

                               Sometimes, the aforementioned is referred to as a "linear equation of two variables," where x and y are the variables.

Given that,

The length of an object object in feet is equal to 3 times it’s length in yards

The length of wall water side slide is 36 feet

Let "y" be the length of object in yards

From given,

Length in feet = 3 times length in yards

    36 =  3 * y

     3y = 36

    y = 36/3

     y = 12

Thus length of waterslide is 12 yards.

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Answer:

1.46

Step-by-step explanation:

We can represent this problem as an array of dots, where each dot represents 0.73 units.

⚫️ ⚫️

We can see that the resulting product of 2 × 0.73 is just the sum of two dots. We can represent this in equation form as:

0.73 + 0.73

Finally, we can execute the addition by adding the tenths and hundredths of each number separately, then adding everything together at the end.

tenths           +  hundredths

(0.70 + 0.70) + (0.03 + 0.03)

1.40 + 0.06

1.46

The goal of elimination is to remove one of the variables by combining the equations together.

Let's say we have an equation with 3 variables:

a + b + c = 0

The goal of elimination is to remove one of the variables by combining the equations together.

Multiply the first equation by a number, n, such that nb + nc = 0

For example:

Let n = -2

-2b + -2c = 0

Add the two equations:

a + b + c = 0

-2b + -2c = 0

a - b = 0

Solve for b:

a - b = 0

b = a

Therefore, the final equation is:

a + a + c = 0

2a + c = 0

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The 7th term of the geometric sequence is 3675/64.

A geometric sequence is a sequence of numbers where each term is found by multiplying the previous term by a constant called the common ratio.

The 7th term of a geometric sequence can be found using the formula:

a_n = a_1 * (r)^(n-1) where a_1 is the first term of the sequence, r is the common ratio, and n is the position of the term in the sequence.

Given that the common ratio is 3/2 and the first term is 5, we can substitute these values into the formula:

a_7 = 5 * (3/2)^(7-1)

After solving the expression we get:

a_7 = 5 * (3/2)^6 = 5* (243/64) = 15*243/64 = 3675/64

So the 7th term of the geometric sequence is 3675/64.

Therefore, the 7th term of the geometric sequence is 3675/64.

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The total weight of the wall is 49,500 lb, and the average dead load per foot of wall length is 1237.5 lb/ft.

To find the total weight of the wall and the average dead load per foot of wall length, we need to calculate the total area of the wall and the area of the windows, then use that information to determine the weight of the remaining brick veneer.

First, we calculate the total area of the wall by multiplying the length and height:

40 ft * 11 ft = 440 ft²

Next, we calculate the area of the windows by multiplying the total area of the wall by 25% (the percentage of the wall that is windows):

440 ft² * 0.25 = 110 ft²

Now we can find the area of the brick veneer by subtracting the area of the windows from the total area of the wall:

440 ft² - 110 ft² = 330 ft²

To find the weight of the brick veneer, we can assume a weight of 150 lb/ft². We can calculate this by multiplying the area of the brick veneer by the weight per square foot:

330 ft² * 150 lb/ft² = 49,500 lb

Now to find the average dead load in lb/ft of the length of the wall, we divide the total weight of the wall by the total length of the wall:

49500 lb / 40 ft = 1237.5 lb/ft

So the total weight of the wall is 49,500 lb, and the average dead load per foot of wall length is 1237.5 lb/ft.

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Answer: 1 3/4 = 35/20 and 1 4/5 = 36/20

Step-by-step explanation:

1 3/4 = 7/4

Multiply top and bottom by 5 to get 35/20

1 4/5 = 9/5

Multiply top and bottom by 4 to get 36/20

The probability that the mean mpg for a random sample of 25 light vehicles is 0.042341

Probability theory, a subfield of mathematics, gauges the likelihood of an occurrence or a claim being true. An event's probability is a number between 0 and 1, where approximately 0 indicates how unlikely the event is to occur and 1 indicates certainty. A probability is a numerical representation of the likelihood or likelihood that a particular event will occur. Alternative ways to express probabilities are as percentages from 0% to 100% or from 0 to 1. the percentage of occurrences in a complete set of equally likely possibilities that result in a certain occurrence compared to the total number of outcomes.

z = (x-μ)/σ/n, where

x is the raw score = 20 mpg

μ is the population mean = 21 mpg

σ is the population standard deviation = 2.9

n = random number of samples [tex]x < 20[/tex]

[tex]= z = 20 - 21/2.9/\sqrt{25} \\= z = -1/2.9/5\\= z = -1.72414\\[/tex]

P-value from Z-Table:

[tex]P(x < 20) = 0.042341[/tex]

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Answer:

a) 400% b) 1/4 c) 64

Step-by-step explanation:

Answer:

a. 400%

b. 25

c. 64

Step-by-step explanation:

a. 160 ÷ 40/100

160 × 100 / 40

4 × 100 = 400%

b. 40 ÷ 160%

40 ÷ 160/100

40 × 100/160 = 25

c. 40% × 160

40/100 × 160

4 × 16 = 64

The mean of negatively skewed data is smaller than the median. If the data are displayed symmetrically, the distribution is not skewed regardless of tail length or thickness. So, option d. is correct.

A skew curve is a type of statistical distribution in which the data are unevenly distributed. This is often called an asymmetric distribution, meaning that the two halves of the curve look different. A skewed curve can be either positively or negatively skewed, depending on the direction in which the data points are shifted. Positively skewed curves tend to have long tails to the right, while negatively skewed curves tend to have long tails to the left. This type of distribution is common in real-world data such as income and wealth distributions.

A negatively skewed curve is indicated by the negative tail of the chart. This means that the data points are likely to be below average. Therefore, the mean is lower than the mode, which is lower than the median. The mean is the arithmetic mean of all data points, the mode is the most common value, and the median is the midpoint of the data points.

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No, 9x2 42x 49 is not a perfect square trinomial.

Perfect squares are numbers that are the product of a number multiplied by itself. Examples of perfect squares include 4 (2 x 2), 9 (3 x 3), 16 (4 x 4), 25 (5 x 5), 36 (6 x 6), 49 (7 x 7), and 64 (8 x 8). Perfect squares are also referred to as "square numbers" or "whole-number squares."

No, 9x2 42x 49 is not a perfect square trinomial. A perfect square trinomial is a polynomial of the form a2 + 2ab + b2,

where a and b are numbers or variables.

9x2 42x 49 does not fit this pattern, as it does not involve two terms whose sum is multiplied by itself.

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The fraction which is equivalent to 4/6 is 8/12 as asked in the question.

2 x 4 = 8 and

3 x 4 = 12

Therefore, they satisfies the condition of an equivalent numbers.

Equivalent numbers are those which on reducing to it's lowest terms gives the same number.

Other example , 2/4 is equivalent number to 8/16 .

Equivalent fractions are those fractions which has different numerators and denominators but the same value when reduced to their lowest terms. For, example 2/4 and 3/6 are comparable fractions because they both equal 12.

A fraction is a portion of a number written in terms of numerator and denominator. Equivalent fractions represent the same percentage of the whole.

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The expression equivalent to -3 - 3x -1x is 4 - 2x.

An expression in math is a sentence with a minimum of two numbers or variables and at least one math operation. This math operation can be addition, subtraction, multiplication, or division. For example, x + y is an expression, where x and y are terms having an addition operator in between. In math, there are two types of expressions, numerical expressions - that contain only numbers; and algebraic expressions- that contain both numbers and variables.

To get to this you can combine like terms:

-3 - 3x - 1x = -3 - (3x + 1x)

= -3 - (4x)

= -3 - 4x

= -4x - 3

= 4 - 2x

Hence  4 - 2x is equivalent to -3 - 3x -1x

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To estimate the true proportion of home owners who have vegetable gardens to within 6 percentage points with confidence, a sample size of 384 would be needed.

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Answer:

Step-by-step explanation:

-x+6=-2(x+2)-5

Solve for x

-x + 6 = -2(x + 2) - 5

-x + 6 = -2x - 4 - 5

x = -15

------------------------

- (-15) + 6 = -2(-15 + 2) - 5

21 = 21

x = -15

Answer: Option D (0.833)

Step-by-step explanation:

There are 6 possible outcomes when the arrow is spun, and 5 of those outcomes correspond to the arrow landing on a number greater than 10 (the numbers 11, 12, 13, 14, and 15).

Therefore, the probability of the arrow landing on a number greater than 10 is 5/6, or about 0.833

The number of books that Sofia read is 32 books and the brother read 8 books.

An equation simply has to do with the statement that illustrates the variables given. In this case, it is vital to note that two or more components are considered in order to be able to describe the scenario.

From the information, Sofia and her brother combined to read a total of 40 books over the summer sofia read four times as many books as her brother how many books did each person read

Let the number of books read by the brother = x

Number of books read by Sofia = 4x

Therefore, x + 4x = 40

5x = 40.

Divide

x = 40 / 5

x = 8

The brother read 8 books

Sofia read = 4x

= 4 × 8

= 32 books.

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Therefore , the solution of the given problem of angles comes out to be

Each inner angle of a regular hexagon measures 120 degrees.

Two rays that converging at the vertex, or center, of an angular structure in geometry make up the structure. We refer to these rays as the faces of the angle. Two beams may well be able to create any angle within just a planar depending on their location. Additionally, an angle is created when two planes intersect. .

Given: A standard hexagon

Measure each internal angle of a standard hexagon.

Solution:

(n - 2) x 180° is the formula for the sum of lengths of a polygon's inner angles.

Every side of a regular polygon is the same length, and every angle is the same size.

A hexagon has six sides.

Find the total of the measurements of the internal angles of a hexagon by substituting n = 6 in (n - 2) x 180n latitude in step 1.

=> (n - 2) * 180°

=> (6 - 2) * 180°

=>4 * 180°

=> 720°

Step 2: Since a regular hexagon has six sides and all of its sides and angles are equal in size, divide by six to obtain the dimensions of each inner angle.

=> 720° /6

=> 120°

Each internal angle of such a regular polygon is 120 degrees in length.

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On solving the provided question we can say that - here in trigonometry [tex]sinx(2cosx - 1) = 0\\[/tex] =>  sinx = 0 and 2 cosx -1 =0

The area of mathematics known as trigonometry examines the correlation between triangle side lengths and angles. The area first appeared in the Hellenistic era, around the third century BC. from the use of geometry in astronomical study. The area of mathematics known as exact methods deals with specific trigonometric functions and how they might be used in calculations. There are six popular trigonometric functions in trigonometry. Sine, cosine, tangent, cotangent, secant, and cosecant are their respective names and acronyms (csc). Studying the characteristics of triangles, particularly right triangles, is called trigonometry. The study of geometry, however, is the characteristics of all geometric figures.

[tex]sin 2x - sinx = 0\\-sinx + 2cosx sinx=0\\sinx(2cosx - 1) = 0\\[/tex]

sinx = 0 and 2 cosx -1 =0

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