Question

In a clinical trial of a cholesterol​ drug, 451 subjects were given a​ placebo, and 21​% of them developed headaches. For such randomly selected groups of 451 subjects given a​ placebo, identify the values of​ n, p, and q that would be used for finding the mean and standard deviation for the number of subjects who develop headaches.

Answer 1

n=451

p=0.21

q=0.79

Explanation:

The value of n is the population size, in this case 451 total subjects that were given placebo. p refers to a sample population with certain attribute, which is the proportion of subjects who develop headaches. In this case the value of p= 21%=0.21. q is the proportion of the population that do not have the attribute in question (headaches). q=1-p, therefore q= 1-0.21=0.79.

To find the standard deviation the formula is: σ= √npq

Substituting the values: σ = √(451)(0.21)(0.79) = 8.65.