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PilotLPTM [1.2K]
2 years ago
12

Researchers randomly choose two groups from 15 volunteers. Over a period of 9 weeks, one group watches television before going t

o 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
Mathematics
1 answer:
inessss [21]2 years ago
3 0

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.

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What is the product of (-1/4)x(-3/7)
Oksana_A [137]

Answer:  Multiply from left to right.

(-3/4)(-4/7)(-2/3)

3/7(-2/3)

-2/7

Step-by-step explanation:

7 0
2 years ago
Help please!!<br> 1. What is the value of n?<br> 2.What is the value of n?
lana66690 [7]

Using the intersecting chord theorem:

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n = 6 m



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4 0
3 years ago
Read 2 more answers
How many books can you get in a storage bin that is 4 feet high and 9 feet long and 11 feet wide
Ugo [173]
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4 0
3 years ago
A pen is being built that is 10 feet long and 20 feet wide. How much fencing material will be ne
schepotkina [342]
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therefore answer is 60 feet 
7 0
3 years ago
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mestny [16]

Answer:

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Step-by-step explanation:

is this Correct

coz I don't get the queen

4 0
3 years ago
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