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professor190 [17]
3 years ago
9

In a study conducted at the University of Chicago, S. Frankel and colleagues studied middle school students in 10 Illinois commu

nities. Each year for 7 years, they measured the lung function of the children and the levels of coal ash particles in the air in the communities. Was this a cohort study or a case-control study? Was the study prospective, cross-sectional, or retrospective?
Pick from the following:
A). This was a retrospective cohort study
B). This was a prospective case-control study
C). This was a retrospective case-control study
D). This was a cross-sectional cohort study
E). This was a prospective cohort study
Mathematics
1 answer:
natali 33 [55]3 years ago
8 0

Answer: D). This was a cross-sectional cohort study

Step-by-step explanation:

The given situation is an example of cross sectional cohort study because the investigator choose the samples from the population using cross sectional method and use the same sample source for analyzing the independent variables for specific period of time or intervals of time to assess the history of exposures and outcomes.

Here, the lung function is tested at an interval of 7 years compared with the levels of exposure to the coal ash so it is the example of cross sectional cohort study.

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3 years ago
150 is 100% of what number?
andriy [413]

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150 is 100% of 150

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We have, 100% × x = 150

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If you are using a calculator, simply enter 150×100÷100, which will give you the answer.

3 0
2 years ago
Prove that sin^4x + cos^4x= sinxcosx
yKpoI14uk [10]

Answer:

(the relation you wrote is not correct, there may be something missing, so I will simplify the initial expression)

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Now we can add and subtract cos^2(x)*sin^2(x) to get:

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If we replace that, we get:

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7 0
3 years ago
Please explain and show work
Vinvika [58]
1*3/5 = 3/5.
3/5(t-6) = -0.4
Distribute 3/5
3/5t - 3.6 = -0.4
Add 3.6 
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t = 5 1/3 or 5.33
6 0
4 years ago
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