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Reaction probability

The probability that a patient will have a negative reaction to a certain medication is 0.03. The medication is administered to 75 patients. What is the expected number of negative reactions?

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Vivian L. | Microsoft Word/Excel/Outlook, essay composition, math; I LOVE TO TEACHMicrosoft Word/Excel/Outlook, essay comp...
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Hi Again Chris;
I love probability questions!
x=(75 patients)(0.03 negative patients/patient)
Let's cancel units where appropriate...
x=(75 patients)(0.03 negative patients/patients)
x=(75)(0.03 negative patients)
x=2.25 negative patients
Obviously, there is no such thing as 0.25 patients.  So...
x=2 negative patients
I would like to stress, always make certain your units cancel appropriately.  If these do not, you are working with the wrong equation.


Expected values need not be integers, so you should leave it as 2.25 patients.