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:

Standard Deviation

A measure of the amount of variation or dispersion of a set of values; a low standard deviation indicates that the values tend to be close to the mean, whereas a high standard deviation indicates that the values are spread out over a wider range.

Mean

The average value of a set of numbers, calculated by dividing the sum of all the numbers by the count of numbers.

Normally Distributed

A statistical distribution that is uniform around its mean, highlighting that data points near the mean are more prevalent than ones at a greater distance.

Standard Deviation

A metric that assesses the spread or diversity among a collection of figures, indicating the degree to which each figure differs from the mean value.