Question

The blood bank at a hospital has 1,200 units of blood, out of which 37% units are of blood group B+. A clinical researcher randomly selects 300 units of blood and finds that 33% of those are of blood group B+. To test his result, he randomly selects 200 units of blood and finds that 40% of those are of blood group B+. Which of the following is the reason there is a difference between the two percentages selected by the researcher?

Answer 1

The reason why the two percentages are different is that the sample does not reflect the characteristics of all the units of blood.

What is sampling?

Sampling is a statistical technique in which a sample of a statistical population is selected for the study. The objective of sampling is to ensure that its properties can be extrapolated to the total population.

Sampling is a way of saving resources, and at the same time obtaining results similar to those that would be achieved if a study of the entire population were carried out.

According to the above, the clinical researcher who selected a sample of the available blood units obtains different percentages because he selected randomly and this can modify the quantities of samples according to blood type.

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