Many people believe that they can tell the difference between Coke and Pepsi. Other people say that the two brands can't be distinguished. To test this, a random sample of 20 adults was selected to participate in a test. After being blindfolded, each person was given a small taste of either Coke or Pepsi and asked to indicate which brand soft drink it was. Suppose 14 people correctly identified the soft drink brand. Which of the following conclusions would be warranted under the circumstance?
A) Since the chance of getting 14 correct is 0.0370, which is quite small, the study shows that people are not able to identify brands effectively.
B) Since the probability of getting 14 or more correct is 0.0577, which is quite low, this means that people are not effective in identifying the soft drink brand.
C) Since the probability of getting 14 or more correct is 0.0577, which is quite low, the conclusion could be that people are effective at identifying soft drink brands.
D) The expected value for this binomial distribution is very close to 14 so this supports that people cannot tell the difference.

Question

Quizplus · Accepted Answer

The probability of getting 14 or more correct identifications out of 20 (assuming a 50% chance of guessing correctly, which is the case if people cannot tell the difference) being low (0.0577) suggests that the outcome is not just due to chance. Therefore, it indicates that people can indeed identify the brands better than random guessing would allow.

Many People Believe That They Can Tell the Difference Between