A researcher is interested in whether using mental imagery can help people remember specific details when given information. To conduct the experiment, the researcher asks 100 volunteers to participate. The researcher places everyone’s name in a hat and randomly selects 50 names, making sure to sure to mix the names between each selection.

Which component is missing from the researcher’s process?

The researcher did not use enough randomization in the process.
The researcher used volunteers instead of randomly selected people from the population.
The researcher did not assign the 50 names to the treatment group or the control group.
The researcher should have used numbers instead of names for confidentiality reasons.

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[tex]\large \sf \underline{Problem:}[/tex]

The perimeter of a rectangle is twice the

sum of its length and its width. The

perimeter is 40 meters and its length is 2

meters more than twice its width.

What is its length?

====================================

[tex]\large \sf \underline{Answer:}[/tex]

The answer is 12 m.

====================================

[tex]

\large \sf \underline{Explanation:}[/tex]

The perimeter (P) of a rectangle is twice the sum of its length (I) and width (w):

P = 2(l + w) P = 34

=>> 2(1+w) = 34

1+ w = 34/2

⇒ I + w = 17

Length is 2 meters more than twice its width:

I = 2w + 2

Now we have the system of equations:

I + w = 17

I = 2w + 2

Use the substitution method and substitute I from the second equation into the first equation:

2w + 2 + w = 17

2w + w = 17 - 2

3w = 15

w = 15/3

w = 5

Now, substitute w into the equation:

I = 2w + 2

I =2* 5+2

I = 10 + 2

I = 12

====================================

Answer:

x = 0

x = -4

x = -3

Step-by-step explanation:

Hello!

First, lets factor out 3x (GCF) from the whole expression:

Factor the polynomial by grouping:

Set the expression and each factor to 0, and solve for x:

3x = 0

x + 4 = 0

x + 3 = 0

There are 3 roots for this equation: 0, -4, and -3.

Answer:

[tex]\dfrac 3{10}[/tex]

Step-by-step explanation:

[tex]~~~~~~\dfrac 25 + x = \dfrac 7{10}\\\\\\\implies x = \dfrac 7{10} - \dfrac 25\\ \\\\\implies x = \dfrac 7{10} - \dfrac 4{10}\\\\\\\implies x = \dfrac{7-4}{10}\\\\\\\implies x = \dfrac 3{10}[/tex]

Solving the inequality, it is found that three values that would make the inequality true are given as follows: y = 12, y = 15, y = 18.

The inequality is given by:

y + 7 > 18.

We solve it similarly to an equality, hence the solution is given as follows:

y > 18 - 7.

y > 11.

Hence three values that would make the inequality true are given as follows: y = 12, y = 15, y = 18.

More can be learned about inequalities at https://brainly.com/question/25235995

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Answer:

ANswer A for Reshawn

Step-by-step explanation:

The box plots show data about the heights, in feet, of two different types of trees at a local nursery.

Which statement is best supported by the information in the box plots?

Answer:

$36.25

Step-by-step explanation:

Shipping and tax are 25% the price of online book, thus it will be 25/100 x 29 = $7.25

Thus, total will be 29 + 7.25 = $36.25

Answer:

In terms of pi: 164.5pi cm squared

Substituting pi for 3.14: 516.53 cm squared

Step-by-step explanation:

3.5^2 = 12.25pi

12.25*2 = 24.5pi

7pi*20 = 140pi

140 + 24.5 = 164.5pi

164.5*3.14 = 516.53

Answer:

≈ 4.7 mm

Step-by-step explanation:

Using Pythagoras' identity in the right triangle

the square on the hypotenuse is equal to the sum of the squares on the other 2 sides.

let x be the missing side , then

x² + 5.2² = 7²

x² + 27.04 = 49 ( subtract 27.04 from both sides )

x² = 21.96 ( take square root of both sides )

x = [tex]\sqrt{21.96}[/tex] ≈ 4.7 mm ( to the nearest tenth )

Answer:

The hypotenuse is 4√5.

Step-by-step explanation:

[tex] \sqrt{ {4}^{2} + {8}^{2} } = \sqrt{16 + 64} = \sqrt{80} = \sqrt{16} \sqrt{5} = 4 \sqrt{5} [/tex]

Answer:

184in.³

Step-by-step explanation:

volume of a pyramid = (1/3) • base_area • height

6 • 92 = 552(1/3) = 184

Answer:

224 sq m

Step-by-step explanation:

We are basically finding surface area of a rectangular prism, minus the top side

[tex]2(2)(8) + 2(16)(2) + 16(8)[/tex]

Simplify:

[tex]32 + 64 + 128 = 224[/tex]

Answer:

-8 - -11 = 3

Step-by-step explanation:

[tex]-8-x=3\\\\-8-x-3=3-3\\\\-11-x=0\\\\-11-x+x=0+x\\\\-11=x[/tex]

Therefore, the missing number is -11

#2^(x-2)

For 2

For 3

For 4

For 5

For 6

#2^x-2

For 2

For 3

For 4

For 5

For 6

Answer:

[tex]\large \begin{array}{| l | c | c | c | c | c |}\cline{1-6}x & 2 & 3 & 4 & 5 & 6\\\cline{1-6} 2^x-2 &2 &6 &14& 30 & 62 \\\cline{1-6} 2^{x-2} & 1&2 & 4& 8& 16\\\cline{1-6}\end{array}[/tex]

[tex]\large \text{$ 2^x-2 $}:[/tex]

[tex]x=2 \implies 2^2-2=2\\x=3 \implies 2^3-2=6\\x=4 \implies 2^4-2=14\\x=5 \implies 2^5-2=30\\x=6 \implies 2^6-2=62[/tex]

[tex]\large \text{$ 2^{x-2} $}:[/tex]

[tex]x=2 \implies 2^{2 -2}=1\\x=3 \implies 2^{3 -2}=2\\x=4 \implies 2^{4 -2}=4\\x=5 \implies 2^{5 -2}=8\\x=6 \implies 2^{6 -2}=16[/tex]

Answer:

B) π/2 units to the right

Explanation:

Function : y = 4sin(2x-π)

f(x) = A * g(Bx - C) + D where C/B is phase shift, D is vertical shift.

Identify: B = 2, C = π, D = 0

Horizontal shift:

Vertical shift:

The position and nature of the image are magnified,

Focal length, usually represented in millimeters (mm), is the basic description of a photographic lens.

Radius of curvature of the mirror, R = -60 cm

Focal length of the mirror, f = -30 cm

Object distance, u = -20 cm

Let v is the position of the mirror. It can be calculated as :

[tex]\rm \dfrac{1}{v}+\dfrac{1}{u}=\dfrac{1}{f}\\\\\dfrac{1}{v}=\dfrac{1}{f}-\dfrac{1}{u}\\\\\dfrac{1}{v}=\dfrac{1}{-30}-\dfrac{1}{-20}\\\\\\\dfrac{1}{v}=\dfrac{-20 - (-30)}{(-30)(-20)}\\\\\dfrac{1}{v}=\dfrac{10}{(-30)(-20)}\\\\\dfrac{1}{v}=\dfrac{10}{600}\\\\\dfrac{1}{v}=\dfrac{1}{60}\\\\v=60[/tex]

The image is formed at a distance of 60 cm behind the concave mirror.

[tex]\rm m=\dfrac{-v}{u}\\\\m=\dfrac{-60}{-30}\\\\m=2[/tex]

The image is magnified.

Hence, the position and nature of the image are magnified,

Learn more about focal length here;

https://brainly.in/question/7222487

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Step-by-step explanation:

1. completing the square

x² + 10x + ... = (x + a)² = x² + 2ax + a²

10 = 2a

a = 5

so,

x² + 10x + 10 = -22

is

(x + 5)² - 15 = -22

(x + 5)² = -7

x + 5 = i×sqrt(7)

the solutions are

x = i×sqrt(7) - 5

x = -i×sqrt(7) - 5

2. is easy via factoring

that means there has to be an easy way to define

x² + 3x - 40 = (x + a)(x + b)

remember,

(x + a)(x + b) = x² + (a+b)x + ab

since the constant term is -40, we know either a or b had to be negative (and the other positive).

a × b = -40

so, what factors deliver 40 ?

1×40

2×20

4×10

5×8

the x-term factor is 3.

so,

a + b = 3.

therefore, it must be the combination 8-5.

so, the factoring is

(x + 8)(x - 5) = 0

the solutions are therefore

x = -8

x = 5

3. quadratic formula

x² + 3x + 1 = 0

a = 1

b = 3

c = 1

x = (-b ± sqrt(b² - 4ac))/(2a)

x = (-3 ± sqrt(3² - 4×1×1))/(2×1) = (-3 ± sqrt(9 - 4))/2 =

= (-3 ± sqrt(5))/2

the solutions are

x = (-3 + sqrt(5))/2

x = (-3 - sqrt(5))/2

therefore

4. 2 non-real solutions (called also complex or irregular)

5. 2 rational solutions

6. 2 irrational solutions

Answer:

The probability is 4 1 because there is four toys and the probability that the kid will get a Mario toy twice in a row has a low chance becuase, there are three other toys

Step-by-step explanation:

Answer:

She's paid 7.50 pounds an hour

Step-by-step explanation:

7.50 x 8 = 60

Answer:

was less affective on males in the study because only 27 % of them lost weight, whereas 3% of the females lost weight.

Step-by-step explanation:

It had less affective on males in the study. And there is a diffrent amount of males and females who tried the weight loss supplement.

hopefully this helps you

- Matthew

Answer:

He would have to talk 200 minutes.

Step-by-step explanation:

Since 30 divided by .15= 200. And there is a .15 cent cost per minute meaning Javier would have to talk for 200 minutes for the prices to be equal.

Have a great day!

Answer:

3.2

Step-by-step explanation:

2e = 6.4

dividing through by 2 in order to make e the subject of the equation

e = 6.4/2

e =3.2

Answer:

A=e(b-c)-d

A=-2(6-3)-4

A=-12+6-4

A=-6-4

A=-10

The measure of the angles are 91.375°and 88.625°. Both the angles are obtained by the supplementary angle principal.

Supplementary angles are two angels whose total is 180 degrees. When a straight line is crossed by a line, two angles develop on each of the examined straight line's sides.

Two sets of additional angles make up those two-two angles. That is, if supplementary angles are placed next to each other, the exterior sides of their exterior sides will form a straight line.

The given data in the problem is;

∠1 = 9y-2

∠2 = 7y+16

The sum of the supplementary angle is 180

⇒9y-2 +7y+16 = 180

⇒16y +14 =180

⇒16y= 166  

⇒ y=10.375

The measure of the angle 1 is;

∠1 = 9y-2

∠ 1 = 9 ×10.375 -2

∠ 1 = 91.375°

The measure of the angle 2 is;

∠2 = 7 × 10.75 +16  

∠2 = 88.625°

Hence, the measure of the angles are 91.375°and 88.625°.

To learn more about the supplementary angle,refer to the link;

https://brainly.com/question/2882938

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If no letters or numbers are repeated, then the number of possibilities will be 11,232,000. Then the probability that the license plate is ABC123 or MOM678 will be 1/8,788,000.

A permutation is an act of putting things or elements in the right sequence. Combinations are a method of picking things or pieces from a collection of objects or sets when the sequence of the objects is irrelevant.

A series of license plates are being produced that all have the same pattern of three letters (a-z) followed by three digits (0-9) without any repeats.

If no letters or numbers are repeated, then the number of the possibilities will be

Number of ways = 26 × 25 × 24 × 10 × 9 × 8

Number of ways = 11,232,000

Then the probability that the license plate is ABC123 or MOM678 will be

[tex]P = \dfrac{1}{17,576,000}+\dfrac{1}{17,576,000}\\\\P = \dfrac{1}{8,788,000}[/tex]

More about the permutation and the combination link is given below.

https://brainly.com/question/11732255

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Answer:

I'm pretty sure the median is 7

Step-by-step explanation:

Well To find the median, first order your data. Then calculate the middle position based on n, the number of values in your data set.

2 2 4 5 5 9 9 12 16 20. Then add the 2 middle numbers. 5 and 9. It is (5+9) divided by 2 is 7.

Hope this helps!

Answer:

0.6 ...........................

Answer:

248 acres

Step-by-step explanation:

A forest covers 31,000 acres

0.8% of the forest old growth trees

There are 0.8% × 31000 = 248 acres of old growth trees

Answer:

=69805

Step-by-step explanation:

This is an exponential growth problem.  If the population doubles periodically, it follows a law like this:

P(t) = P(0)e^kt

where P(0) is the initial population at time t=0, and k is a constant with units of years-1.

To find k, let t=0.  Then P(t) = P(0) = initial population = 2183.

Since the population doubles every 28 years, we can write

P(t+28) = 2P(t)

P(0)ek(t+28) = 2[P(0)e^kt] 

Simplifying,

e²⁸k = 2

k = ln(2) / 28 = 0.02475 years-¹

Finally,

P(t) = 2183e⁰.⁰²⁴⁷⁵t, t in years

P(t)= 2183e^0.02475t, t in years

Then at t=140 years from now,

P(140) = 2183e⁰.⁰²⁴⁷⁵×¹⁴⁰

P(140) = 2183e^(0.02475 × 140) = 69804.61168

=69805

Answer: 69,856

Step-by-step explanation: First, find out how many times the population will double. Divide the number of years by how long it takes for the population to double.

140÷28=5

The population will double 5 times.

Now figure out what the population will be after it doubles 5 times. Multiply the population by 2 a total of 5 times.

2,18322222=69,856

That calculation could also be written with exponents:

2,18325=69,856

After 140 years, the population will be 69,856 people.

We have the point (3, 22.5), which means every 3 candles, Victor gains 22.5 dollars.

Similarly to the point (7, 52.5), which means every 7 candles, Victor gains 52.5 dollars.

-> Every 1 candle, Victor gains 7.5 dollars.

Answer:

Step-by-step explanation:

Corresponding angles equal 180 degrees when added

6x + 3x = 180

9x = 180

x = 20

angle CBD is 60 and angle GFH is 120

3(20) = 60

6(20) = 120