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Xelga [282]
3 years ago
11

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

er nominate if the study type is
descriptive, analytical or experimental and also provide two (2) reasons for your choice of study type

(for example, if you believe a particular description relates to a Cross-Sectional study nominate if it is an example of a descriptive, analytical or experimental study type AND provide two (2)reasons why you believe it is a Cross-Sectional study).

KEY (Study Type)

A Descriptive study
B Ecological study
C Cross-Sectional study
D Case-Control study
E Retrospective Cohort study
F Prospective Cohort study
G Randomised Controlled Trial
H Community Trial

a) A total of 825 insulation workers employed between 1941 and 1944 was identified from the personnel records of three large insulation manufacturing plants in the south-eastern United States in 1975. During the period 1941-1975, 26 deaths from lung cancer were discovered among the workers. Only six lungcancer deaths, however, were reported among a comparable group of 700 coworkers who did not work with insulation during the same time period. The investigators had postulated that exposure to the insulation material increases the risk of lung cancer.

b ) To see if hypnosis could reduce chronic pain, investigators randomly assigned 120 volunteers with osteoarthritis to either hypnosis therapy or a control group. Pain levels were checked among the subjects every three months during the 12- month study using validated pain measures. Those assigned to the hypnosis group reported reduced pain compared to those in the control group after three and six months, but not after nine and 12 months, of follow-up.

c) To find out if planting grass on the top of buildings would be effective in reducing air pollution levels in polluted cities, investigators selected two adjacent cities with similar demographic profiles and air pollution levels. The officials of one city agreed to plant grass on all its public buildings in the downtown area and on all private buildings where consent could be obtained. The other city did not plant any grass on the top of its buildings. After two years of follow-up, the city that planted grass on the buildings had lower air pollution levels than the city that did not plant any grass, although the difference was not significantly different.

d) A study was undertaken to test the hypothesis that chewing tobacco increases the risk of stomach cancer. Detailed historical data on chewing tobacco use were collected from 400 subjects with newly diagnosed stomach cancer and 400 subjects without stomach cancer. The results revealed that chewing tobacco was not a significant risk factor for stomach cancer.
Mathematics
1 answer:
emmasim [6.3K]3 years ago
4 0

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!

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If a diameter intersects a chord of a circle at a right angle, what conclusion can be made?
drek231 [11]

Answer:

The chord is bisected.

Step-by-step explanation:

see the attached figure to better understand the problem

In the circle of the figure

The diameter is the segment DE

The chord is the segment AB

PA=PB=r ----> radius of the circle

Triangles PAC and PBC  are congruent right triangles by SSS

Because

PA=PB

PC is a common side

AC=BC ----> Applying Pythagoras Theorem

therefore

The chord AB is bisected

6 0
3 years ago
Read 2 more answers
Steve and Ben have some money in their wallets. If Steve gives Ben $3, Ben will have twice as much as Steve. If Ben gives Steve
Zigmanuir [339]

Answer:

Money owned by Steve = $11

Money owned by Ben = $13

Step-by-step explanation:

Let x denotes the money owned by Steve and y denotes the money owned by Ben.

Then, Steve gives $3 to Ben

Money left with Steve = x-3 and Ben = y+3

Now, Ben will have twice as much as Steve.

⇒ y+3  = 2(x-3) .............(1)

If Ben gives Steve $7

Money left with Steve = x+7 and Ben = y-7

Then,  the amount Ben has will be one-third that of Steve’s.

⇒ y-7 = \frac{1}{3} (x+7) ..........(2)

Solving equation (1) and (2) by elimination method, we get

x = 11 and y = 13

⇒ Money owned by Steve = $11

Money owned by Ben = $13

5 0
2 years ago
The same amount of principal is invested in different accounts earning the same interest rate. Which of the following
olchik [2.2K]

The answer is D: An account earning interest compounded daily.

5 0
2 years ago
Easy 20 points please tell me if I got it right and if not please tell me the right answer
mash [69]

Answer:

No, you are not correct.

It should look like this:

                              Prefer colorful decorations      Prefer neutral decorations

Pay attention                           20                                                  25

to fashion

Do not pay

attention to                              72                                                      33

fashion

Step-by-step explanation:

33 is 22% of 150. In the question it states that 70% of people do not pay attention to fashion. We need to find the other 48% here. In order to do that we multiply .48 by 150. That gets us 72. To check that answer you can add both 72 and 33 and then divide by 150, which gets 70%.

To get the amount of people that prefer neutral decorations and pay attention to fashion we need to add up 20 + 72 + 33 and that equals 125. Next, we take 150 and minus 125 of it to get 25.

<em>Hope this helps!!</em>

<em>- Kay :)</em>

3 0
2 years ago
The dimensions of a 4-in. square are multiplied by 3. How is the area affected? {Show work!}
Strike441 [17]
If dimensions are multiplied by 3 then area is multiplied by 3^2
3 0
3 years ago
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