You are making a mountain out of a mole hill I think:
.24 * 20 is the number that have been told
20 - .24*20 = number that have not been told
Based on the data collected by the National Centre for health Statistics and made available to the public in the Sample Adult database, it was found that the percentage of adults who have at some point in their life been told that they have hypertension was 24 percent. Suppose that a random sample of 20 adults is taken. What is the expected number of the adults that have not been told that they have hypertension?
I believe this is a binnomal random variable. What I don't understand is how do you calculate a variable? I can get the probabilty when given a variabl (eg. P(X<3)). Not the other way round.
Please help.
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1 answer