Question

In a clinical trial of a cholesterol​ drug, 321 subjects were given a​ placebo, and 7​% of them developed headaches. For such randomly selected groups of 321 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. The value of n is ____

Answer 1

Answer: The value of n is 321.

Step-by-step explanation:

Since we have given that

Sample size = 321

Percentage of them developed headaches = 7%

So, the value of p would be

$\dfrac{x}{n}=\dfrac{7}{100}=0.07$

Now, the value of q would be

$q=1-p\\\\q=1-0.07\\\\q=0.93$

And the mean for the number of subjects who develop headaches would be

$n=pq\\\\n=0.07\times 0.93\\\\n=0.0651$

and the standard deviation would be

$\sigma=\sqrt{npq}\\\\\sigma=\sqrt{321\times 0.07\times 0.93}\\\\\sigma=4.571$

Hence, the value of n is 321.