Determine What Type of Observational Study Is Described

question 55

Multiple Choice

Determine what type of observational study is described. Explain.
-Vitamin D is important for the metabolism of calcium and exposure to sunshine is an important source ofvitamin D. A researcher wanted to determine whether osteoperosis was associated with a lack of exposure tosunshine. He selected a sample of 250 women with osteoperosis and an equal number of women withoutosteoperosis. The two groups were matched - in other words they were similar in terms of age, diet,occupation, and exercise levels. Histories on exposure to sunshine over the previous twenty years wereobtained for all women. The total number of hours that each woman had been exposed to sunshine in theprevious twenty years was estimated. The amount of exposure to sunshine was compared for the two groups.

• A) retrospective; Individuals are asked to look back in time
• B) cross-sectional; Information is collected at a specific point in time.
• C) cohort; Individuals are observed over a long period of time.

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Definitions:

Saturated Zone

The part of the earth's crust where the pores and fractures are filled with water, below the water table.

Pore Spaces

Voids or gaps within a material or soil, which can contain air or fluids.

Water Table

The upper surface of the zone of saturation in the ground, below which the soil, gravel, or rock is saturated with water.

Subsurface Material

Materials found beneath the Earth's surface, which can include soil, rock, liquids, and gases.