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love history [14]
3 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]3 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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A p + 10. Addition is having/giving more. Lynn has more then Carol, so if she has 30, Lynn has 40. So the answer is A.
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3 years ago
Read 2 more answers
PLEASE HELP NEED THIS TO PASS
yaroslaw [1]

The solutions to f(x) = 64 is x = 7 and x = –7.

Solution:

Given data:

$f(x)=x^{2}+15 – – – – (1)

f(x)=64 – – – – (2)

To find the solutions to f(x) = 64.

Equate equation (1) and (2), we get

x^2+15=64

Subtract 15 from both sides of the equation.

x^2+15-15=64-15

x^2=49

x^2=7^2

Taking square root on both sides of the equation, we get

x = ±7

The solutions to f(x) = 64 is x = 7 and x = –7.

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3 years ago
Sara hired her brother James to help her sell
Natasha_Volkova [10]

Answer:

3 Lemonade

Step-by-step explanation:

We add $1.00 with $0.10, then we get $1.10

We then divide $1.10 to the amount Sara paid

$3.60/1.10, we will get the answer 3

8 0
3 years ago
Nadya has 19 1/4 yards of ribbbon she cuts ribbon into peices that measure 1 3/4 how many pieces of ribbon doe Nadya have?
tiny-mole [99]

Answer:

11

Step-by-step explanation:

Well basically i took 19 1/4 and divided it by 1 3/4 and there for i got 11. YOUR WELCOME.

4 0
3 years ago
1. y = x2 + 8x + 15<br> Find the zeros of the function by rewriting the function in intercept form
lubasha [3.4K]

The zeros of given function y=x^{2}+8 x+15 is – 5 and – 3

<u>Solution:</u>

\text { Given, equation is } y=x^{2}+8 x+15

We have to find the zeros of the function by rewriting the function in intercept form.

By using intercept form, we can put value of y as  to obtain zeros of function

We know that, intercept form of above equation is x^{2}+8 x+15=0

\text { Splitting } 8 x \text { as }(5+3) x \text { and } 15 \text { as } 5 \times 3

\begin{array}{l}{\rightarrow x^{2}+(5+3) x+5 \times 3=0} \\\\ {\rightarrow x^{2}+5 x+3 x+5 \times 3=0}\end{array}

Taking “x” as common from first two terms and “3” as common from last two terms

x (x + 5) + 3(x + 5) = 0

(x + 5)(x + 3) = 0

Equating to 0 we get,

x + 5 = 0 or x + 3 = 0

x = - 5 or – 3

Hence, the zeroes of the given function are – 5 and – 3

5 0
3 years ago
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