Researchers randomly choose two groups from 15 volunteers. Over a period of 9 weeks, one group watches television before going to sleep, and the other does not. Volunteers wear monitoring devices while sleeping, and researchers record dream activity. Which type of study method is described in each situation? Group of answer choices a) observational study b) controlled experiment c) survey

Answers

Answer 1

Answer: B. Controlled experiment

Step-by-step explanation:

This is a controlled experiment because the variables in the question are manipulated by the researcher. We are told that while one group watches television before going to sleep, the other group does not.

The controllers won't have control over the variables that were used if it was an observational study while for a survey, it has to do with collection of information regarding certain topics or happenings in order to have people's perception on the topic or area of interest.


Related Questions

The Earth is approximately a sphere of
diameter 12742 km. The surface area
of a sphere is given by the formula A =
4π r2 Calculate the surface area of the
Earth. Give your answer in metres
squared and in standard form.

Answers

Answer:

2

Step-by-step explanation:

Select the equation which represents the graph.
Question 1 options:

A: y − 3 = 3/2(x − 4)

B: y − 3 = 2/3(x − 4)

C: y − 3 =− 2/3(x − 4)

D: y − 3 = −3/2(x − 4)

Answers

Answer:

B. [tex] y - 3 = \frac{2}{3}(x - 4) [/tex]

Step-by-step explanation:

We can create an equation to represent the graph in point-slope form, given as [tex] y - y_1 = m(x - x_1) [/tex], by using a point (x1, y1) on the line, (4, 3) and the slope (m) of the line.

Let's find slope using the two points (4, 3) and (-2, -1).

[tex] slope (m) = \frac{y_2 - y_1}{x_2 -x_1} = \frac{-1 - 3}{-2 - 4} = \frac{-4}{-6} = \frac{2}{3} [/tex]

Substitute m = ⅔, x1 = 4, and y1 = 3 in [tex] y - y_1 = m(x - x_1) [/tex].

The equation that represents the graph would be:

✅[tex] y - 3 = \frac{2}{3}(x - 4) [/tex],

10. +
10. LCM and GCF
Sweet Charlotte has 24 pounds of popcorn, 36 pounds of fudge,
and 144 pounds of lollipops. They will ship out boxes that
contain all 3 items. Each box will have the same amount of
popcorn, fudge, and lollipops. What is the max number of boxes
they can ship out?
A 2 boxes B. 4 boxes C 12 boxes D. 24 boxes
A
B

Answers

Answer:

12 boxes or C.

Step-by-step explanation:

Max = divide.

GCF=12.

LCM = 144.

Difference:

144/12 or 12.

So 12 boxes

Hope this helps :D

Is this a function?
[tex]y= -3x^{2} +10[/tex]

Answers

Answer:

y=-3x^2+10 is a quadratic function, so Yes it is a function.

The area width is 9ft the total is 27ft

Answers

Answer:

3ft

Step-by-step explanation:

because 9 times 3 equal 27

Kendra was asked to find the number of students who planned to attend the evening symphony performance. She was told that 40 percent of the 50 students planned to attend. Kendra’s work is shown below.

Answers

Answer:

KENDRA SHOULD DIVIDE IT BY 2

Step-by-step explanation:

Answer:

The correct answer is B.

Step-by-step explanation:

Hope it helps

just did quiz   (┬┬﹏┬┬)

30 treadmills to 36 elliptical machines ratio simplest form

Answers

Answer:

5 to 6 or 5:6 or 5/6

Step-by-step explanation:

30/36 = 15/18 = 5/6

Answer:

5 treadmills to 6elliptical machines

Step-by-step explanation:

It costs $3.75 for 25 oz. of candy or $6.30 for 90 oz. of candy. Which is
a better buy?*
O 25 oz.
O 90 oz.

Answers

Answer:

90 OZ.

Step-by-step explanation:

You have to divide the ounces by the price to see how much $1 per ounce costs.

25 divided by 3.75 = 6.6 Ounces for $1

90 divided by 6.30 = 14.28 ounces for $1

i need the answer asap please hurry i give you 5 stars
Explain in detail how would you plot the points –1, 5, –2.5, –3, and 2 on the number line. What is the order of the numbers?

Answers

Answer: -3, -2.5, -1, 2, 5.

Explanation:
The number line goes from the smallest number to the largest number. As an example you may ask why -3 is smaller than -1 even though it looks larger. This is because it actually isn’t since it is negative. When a number is negative, the higher the number are the smaller it is. One more example could be that -10 is smaller than -5.
Hi I. Jenny te he he te D answer

Determine if the triangles are congruent. If so, write a congruence statement. Explain
your reasoning in a short paragraph proof.

Answers

Answer: Yes, there are congruent.

Step-by-step explanation: A triangle is congruent if the same shape and size. In this figure, they're congruent.

I hope this helps you!

what's the slope of
(4,5) & (-1,-5)
helppppp

Answers

Answer:

the slope is 2 :)

Step-by-step explanation:

Answer:

it's 2

Step-by-step explanation:

= Find the slope of a line that goes through the (-3,2) and (1,5)

PLz helpp Im confused on this

Answers

Answer:

-2/3 (fraction)

Step-by-step explanation:

Answer:

The slope is [tex]\frac{3}{4}[/tex].

Step-by-step explanation:

[tex]m=\frac{rise}{run}=\frac{5-2}{1+3}=\frac{3}{4}[/tex]

Hope this helps.

Write the equation of the line that passes through the points (-8,6) and (9,-8).
Put your answer in fully reduced point-slope form, unless it is a vertical or horizontal
line.

Answers

Y-6=-14/17 times (x+8) is the correct answer:)

Kristin wants to make 12 ml of an 8% alcohol solution by mixing together a 32% alcohol solution and pure water. How much of each solution must she use? Please put how many ml for the solutions.

Answers

Answer:

To obtain a solution of 12 ml of 8% alcohol, 3 ml of 32% alcohol and 9 ml of water should be used.

Step-by-step explanation:

To determine the amount of 32% alcohol and pure water needed to make a 12 ml 8% alcohol solution, the following calculation is necessary:

If in 12 ml it is sought that 8% of the solution is alcohol, this percentage implies a presence of 0.96 ml of alcohol in the solution.

Now, 12 ml of 32% alcohol has 3.84 ml of alcohol in it, which must be lowered with water to access that amount.

Therefore, since 32/8 is equal to 4, a quarter of the solution composed of 32% alcohol must be placed, while the remaining three-quarters must be pure water.

In conclusion, to obtain a solution of 12 ml of 8% alcohol, 3 ml of 32% alcohol and 9 ml of water should be used.

Solve the following equations using the partial quotients strategy.
1. 8,397 ÷ 27 = __________ 2. 9,396 ÷ 18 = __________ 3. 8,442 ÷ 14 = __________

Answers

Answer:

1. 8,397 ÷ 27 =311

2. 9,396 ÷ 18 =522

3. 8,442 ÷ 14 =603

Step-by-step explanation:



how many solutions to that problem

Answers

Answer:

NO solution

this is absolute value meaning whatever is in the signs l    l   will come out to a positive. THis cant posibly equal a negative

Step-by-step explanation:

f(x)=(x-3) ²+5 determine the vertex

Answers

Answer:

The vertex is (3,5)

Step-by-step explanation:

Brainliest please


What is 40% of 5?
i need help

Answers

Answer:

2

Step-by-step explanation:

Franco and Marcia getting high speed Internet access at the same time. Francos provider charges $60 for installation and $42.95 per month. Marshals provider has free installation and charges $57.95 per month. After how many months will Franco and Marsha have paid the same amount for high-speed Internet service?

Answers

Answer:

4 months

Step-by-step explanation:

Franco's provider = 60 + 42.95x

Marshal's provider = 57.95x

Where,

x = number of months

Equate both charges

Franco's provider = Marshal's provider

60 + 42.95x = 57.95x

Subtract 42.95x From both sides

60 + 42.95x - 42.95x = 57.95x - 42.95x

60 = 15x

Divide both sides by 15

60 / 15 = 15x / 15

4 = x

x = 4 Months

Franco and Marshal would have paid the same amount for high-speed Internet service after 4 months

what is the fraction of 23%​

Answers

Answer:

23/100

Step-by-step explanation:

is this what u mean?

Answer: is 23/100

im rite

on

ma

mama

En un juego se tiene una ficha, donde un lado dice ganar y otro dice perder. Si se ha lanzado 3 veces la ficha y en todos a salido el lado que dice ganar. ¿Cuál es la probabilidad de que en el cuarto lanzamiento también salga el lado que dice ganar?

Answers

Answer:

no existe una probabilidad ya que es un juego de azar pero si queres la cuarta victoria deberias calcular muchas cosas como el angulo para tirar la ficha y calcular la fuerza etc

Step-by-step explanation:

Circle the ratio which is the same as 1 cm represents 2m
1:2
1:20
1:200
1:2000​

Answers

Answer:

1 cm: 200 cm (if they don't give units) (most likely this answer) (1:200)

if the units are centimeter and meter though, then it's

1:2

Step-by-step explanation:

there are 100 cm in 1 meter, so 1cm:2m

is actually 1cm : 200cm

Solve
28 - K _> 7(K - 4)

Answers

Answer:

Solving the inequality [tex]28-K\geq 7(K-4)[/tex], we get [tex]\mathbf{K\leq 7}[/tex]

Step-by-step explanation:

We need to solve the inequality [tex]28-K\geq 7(K-4)[/tex]

Using the BODMAS rule, first we will solve the bracket:

[tex]28-K\geq 7(K-4)\\28-K\geq 7K-28[/tex]

Now, we will subtract 28 from both sides

[tex]28-K-28\geq 7K-28-28\\-K\geq 7K-56[/tex]

Subtracting -7k on both sides

[tex]-K-7K\geq 7K-56-7K\\-8k\geq -56[/tex]

Finally, divide both sides by -8 and inverse the inequality, as we are dividing with a minus digit.

[tex]\frac{-8K}{-8}\leq \frac{-56}{-8}\\K\leq 7[/tex]

So, solving the inequality [tex]28-K\geq 7(K-4)[/tex] we get [tex]\mathbf{K\leq 7}[/tex]

heeeeeeeeeeeeeeeeeeeeeelp

Answers

Answer:

-2

Step-by-step explanation:

Date


0.5


/


Ration


Question


The boiling point of jet fuel is 329°F.


Rounded to the nearest degree, what is


the temperature in degrees Celsius?


Use the formula C = (F – 32), where


C represents degrees Celsius and F


represents degrees Fahrenheit.

Answers

Answer:

Boiling point of jet fuel = 165 degrees Celsius

Step-by-step explanation:

Given:

Boiling point of jet fuel = 329°F

Find:

Boiling point of jet fuel in degrees Celsius

Computation:

C = [5/9][F – 32]

C = [5/9][329 – 32]

C = 165

Boiling point of jet fuel = 165 degrees Celsius

triangle ABC and DEF are similar what is the length of segment DF?

Answers

Answer:

Proportionate to whatever length the corresponding segment for the similar triangle.

Express log(2)A in terms of the 2 logarithms of prime numbers:
A= √3 * (4th root)(125)) / 7^3

Answers

Answer:

3

125

=

3

5

3

=

5

Step-by-step explanation:

Answer:

1/4 log2 1125 - 3 log2 7

Step-by-step explanation:

A= √3 * (4th root)(125)) / 7^3 =(4th root) (9*125) / 7^3 =(4th root) (1125) / 7^3

Finding logarithm

log2 A = log2 (4th root) (9*125) / 7^3 = 1/4 log2 1125 - 3 log2 7

ASAP There are 25 female performers in a dance recital. The ratio of men to women is 3:5. How many men are in the dance recital?

Answers

Answer:

15

Step-by-step explanation:

whats the slope of the line y-9=15 x-5

Answers

The correct slope is 15:)

Answer:

Slope= 15

Hope this helps! :)

A gym is selling monthly memberships for $35 each and reusable water bottles for $9 each. The gym
needs to make $1188 by the end of the month.
Enter a linear equation that describes the problem.
An equation for the amount of money made by the gym is = $1188, where m is the number of
monthly memberships sold, and w is the number of reusable water bottles sold.

Answers

Answer:

x = gym memberships, and y = bottles of water

30x + 7y = 1050.....when x = 28

30(28) + 7y = 1050

840 + 7y = 1050

7y = 1050 - 840

7y = 210

y = 210/7

y = 30....so he would have to sell 30 water bottles

Step-by-step explanation:

Answer:

1188=35m+9w

Step-by-step explanation:

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