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love history [14]
4 years ago
12

A study is conducted to determine if the blue light from a tablet device will affect the fall asleep time of people in various a

ge groups differently. Volunteers for the study are grouped by age: 18-30, 31-50, and 50. Half of each group is assigned a standard tablet, the other half is assigned a tablet with reduced blue light. People in each group are asked to use the tablet for 10 minutes before bed and their fall asleep time is recorded. Which of the following is correct?
a. Blocks: the three age groups. Treatments: using the standard tablet or the reduced blue light tablet before bed. Response variable: How the eyes react to blue light.
b. Blocks: the three age groups. Treatments: measuring how long it takes to fall asleep. Response variable: The hours of sleep recorded.
c. Strata: the three age groups. Treatments: using the standard tablet or the reduced blue light tablet before bed. Response variable: How the eyes react to blue light.
d. Blocks: the three age groups. Treatments: using the standard tablet or the reduced blue light tablet before bed. Response variable: Time it takes to fall asleep.
e. Blocks: the group receiving the standard tablet and the group receiving the reduced blue light tablet. Treatments: using the standard tablet or the reduced blue light tablet before bed. Response variable: Time it takes to fall asleep.
Mathematics
1 answer:
stepan [7]4 years ago
6 0

Answer: (d) Blocks: the three age groups. Treatments: using the standard tablet or the reduced blue light tablet before bed. Response variable: time it takes to fall asleep

Step-by-step explanation:

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swat32

Answer:

I would say the answer is B

5 0
3 years ago
Read 2 more answers
The temperature in Columbus, Ohio, on Monday is 35 degrees warmer than it was on Sunday. Saturday's temperature was 7 degrees co
lawyer [7]

Answer:

Friday: 45º

Saturday: 23º

Sunday: 30º

Monday: 65º

Step-by-step explanation:

Given that the temperature in Columbus, Ohio, on Monday is 35 degrees warmer than it was on Sunday, while Saturday's temperature was 7 degrees cooler than Sunday's and, at 45 degrees, Friday's temperature was 22 degrees warmer than Saturday's, to determine the temperature of each day the following calculations must be carried out:

Friday: 45º

Saturday: 45º - 22º = 23º

Sunday: 23º + 7º = 30º

Monday: 30º + 35º = 65º

5 0
3 years ago
The radius of a sphere is 6 inches. Find the length of a chord connecting two perpendicular radii. x = inches
Lilit [14]
<h3>Answer:</h3>

6√2 ≈ 8.485 inches

<h3>Step-by-step explanation:</h3>

The radii and the chord together make an isosceles right triangle with legs 6 inches long. The hypotenuse of such a triangle is √2 times the leg length. So, the chord will be 6√2 in long.

_____

<em>Comment on isosceles right triangle</em>

It is worth remembering that the hypotenuse of an isosceles right triangle is √2 times the leg length. This is easily found using the Pythagorean theorem:

... c² = a² + b²

... c² = 1² + 1² = 2 . . . . for legs of length 1

... c = √2 . . . . . . . . . . take the square root.

Scale this result as needed for any particular problem. Here, the scale factor is 6 inches.

3 0
3 years ago
Solve the given equation over the interval [0, 2π): csc^2 x + 2 csc x = 0.
Anastaziya [24]
csc^2x+2cscx=0
Factor out the GCF which is csc x
cscx(cscx+2)=0
Set each factor equal to zero.
cscx=0  or cscx+2=0
Using the reciprocal sine function we can replace csc in the equations.
\frac{1}{sinx} =0  or \frac{1}{sinx} +2=0
The first equation yields 1 = 0 which is not true. However the second equation does offer 2 possible answers.
When solved for sinx you get 
sinx=- \frac{1}{2}
The sine function is negative in the 3rd and 4th quadrants.
You can use the unit circle or the 
sin^-^1 feature on your calculator  sin^-^1(1/2)
210^o  or 330^o  alter radian answer which is probably what you want is \frac{7 \pi }{6}    or   \frac{11 \pi }{6}

8 0
3 years ago
Can you Graph y= 2/3x -4, please
mel-nik [20]

Quite a vague question, I used desmos to graph the attached photo.

3 0
4 years ago
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