Please see the attached file.

. In a clinical test of the drug lipitor, 16.7% of the subjects treated with 10mg experienced headaches.
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The probabilities were obtained by entering the values of n = 6 and p = 0.167. In a clinical test of the drug lipitor, 16.7% of the subjects treated with 10mg experienced headaches. In each case, assume that 6 subjects are randomly selected and treated with 10 mg of atorvastatin, then find the indicated probability.

Binomial with n = 6 and p = 0.167000

X P(X = x)
0.00 0.3341
1.00 0.4019
2.00 0.2014
3.00 0.0538
4.00 0.0081
5.00 0.0006
6.00 0.0000

Yes, the above table was set very correctly.

26. Find the probability that at most two subjects experience headaches. Is it unusual to have at most two of six subjects experience headaches?

From the above table, we know that the probability that at most two subjects experience headaches is
P(X=0)+P(X=1)+P(X=2)=0.3341+0.4019+0.2014=0.9374

We know that the expected number of subjects experience headaches is

E(X)=np=6*0.167=1.002

So, with probability 0.9374 that at most two subjects experience headaches is usual.