Question

An experimental drug was given to a sample of 87 hospital patients with an unknown sickness. Of the​ total, 63 patients reacted​ favorably, 13 reacted​ unfavorably, and 11 were unaffected by the drug. Assume that this sample is representative of the entire population. If this drug is given to Mr. and Mrs. Rivera and their son​ Carlos, what is the probability that all three react​ favorably? (Assume​ independence.)

Answer 1

Ans:

Each time papatient is selected, the number of patients remaining decreases by one. Since the new medicine was given to 87 patients

among these 87 patients, 63 patients reacted favorably, so the probability ofchoosing a patient who reacted favorably is 63/87 =

0.724137931

If the first patient reacted favorably, of the 86 remaining patients 62 patients are left who reacted favorably.

The probability of selecting a second patient who reacted favorably is = 62/86 = .

0.720930233

If the second patient reacted favorably of the 85 remaining patients 61 patients are left who reacted favorably.

The probability of selecting a third patient who reacted favorably is = 61/85 = .

0.717647059

Now the probability of all three react​ favorably = 63/87 *62/86 * 61/85 =

0.37465