How many classifications shown contain organisms whose cells do not have nuclei?

Using the key below, classify each of the following descriptions of epidemiologicalstudies according to study type. In your answ

emmasim [6.3K]

Answer:

Answers are written in BOLD in the explanation below.

Step-by-step explanation:

(A) The study was done in 1975 but the 825 insulation workers were employed or worked between 1941 and 1944. This makes the study a RETROSPECTIVE study.

There is an exposed group (insulation workers) and an unexposed group (coworkers who did not work with insulation). In addition (an additional reason), the study begins with exposed patients and then unexposed patients. These reasons make it a COHORT study.

This study is also an ANALYTICAL study, as the investigators made a postulation, based on analysis of the number of lung cancer deaths among non-insulation workers and the number of lung cancer deaths among insulation workers.

This is also an ECOLOGICAL study, as study results are applicable only at population level.

(B) This is an EXPERIMENTAL study, as the researcher/investigator seeks new knowledge by selecting groups to derive certain data from; in a step by step manner.

Due to the random selection of subjects (volunteers) and random assignment of them to the two groups, this is a RANDOMIZED TRIAL.

The presence of similar experimental and control groups (all volunteers/subjects have osteoarthritis) is a key feature of RANDOMIZED CONTROLLED TRIAL.

After the selection of subjects, experiment of pain levels was conducted for some months (up to a year). This makes the study a PROSPECTIVE study because there was follow-up on the groups, to see who develops the outcome of interest.

The fact that there was no experimental report after 9 and 12 months of follow-up is another key feature of the RCT because in a RCT, the investigator often faces issues like dropout and noncompliance of subjects.

(C) This is a COMMUNITY TRIAL study because two cities/communities are experimented on.

This is also an EXPERIMENTAL study. The fact that both cities have similar demographic profiles and air pollution levels confirms a key feature of experimental studies. There is a 2-year follow-up. This is another reason why the study is experimental and PROSPECTIVE.

(D) This is an OBSERVATIONAL study. This is because already available data was collected and simply looked upon or observed, to know if chewing tobacco was a significant risk factor for stomach cancer.

The data is historical data, hence this is a RETROSPECTIVE study.

This is also a CROSS-SECTIONAL study because it is observational in nature and it gives characteristics of subjects at a single point in time, not over a period of time. It does not have a follow-up period and cannot provide cause-effect relationship between variables.

GOODLUCK!

4 0

3 years ago

X-y=-3<br> Anyone know how to do this ?

horsena [70]

X - y = -3

Move constant to the left by adding its opposite to both sides

x - y + 3 = -3 + 3

The sum of two opposites equals

your answer would be: x - y + 3 = 0

7 0

2 years ago

The area of a square can be represented by the trinomial 9x^2 - 54x + 81. Which of the following is the length of one side of th

Mnenie [13.5K]

$Use\ (a-b)^2=a^2-2ab+b^2\\\\9x^2-54x+81=\underbrace{(3x)^2-2(3x)(9)+9^2}_{(*)}=(3x+9)^2\\\\\text{The formula of an area of a square with a side x:}\ A=x^2.\\\\\text{Therefore we have answer:}\ The\ length\ of\ side\ of\ the\ square\ is\ 3x+9.$

3 0

3 years ago

What is 43.78 in word form

34kurt

Forty three. seven eight

6 0

3 years ago

Read 2 more answers

Can someone please help me, i don't understand this work.

Oksana_A [137]

Answer: Check out the diagram below for the filled out table

Equation is y = 1.5x

Box for row one = 330

Box for row two = 1000

Box for row three = 1.5

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Explanation

x = amount of fish in grams (horizontal axis)
y = number of calories (vertical axis)

The point (x,y) = (200,300) is on the blue diagonal line. It indicates that x = 200 grams of fish have y = 300 calories. Divide the two values to get the slope

slope = y/x = 300/200 = 1.5

This trick only works because the line is going through the origin. Otherwise, we'd have to use the slope formula.

The slope of 1.5 is the constant of proportionality. It tells us the equation is y = 1.5x. Whatever x is, multiply by 1.5 to get y.

So if x = 220, then y = 1.5x = 1.5*220 = 330

220 grams of fish have 330 calories. We'll write 330 in the box of the first row of the table.

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We can use this idea in reverse. If we know the calorie count (y), then we can divide by 1.5 to get the number of grams (x).

y = 1.5x

1500 = 1.5x

1.5x = 1500

x = 1500/(1.5)

x = 1000

Therefore, 1000 grams of fish have 1500 calories. We'll write 1000 in the box of the second row.

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The third row of the table is going to follow the same steps as the first row.

y = 1.5x

y = 1.5*1

y = 1.5

One gram of fish produces 1.5 calories

The filled out table is shown below. I've merged the two screenshots you posted into one image, and filled out the boxes.

8 0

2 years ago