Question: The members of 13 pairs of identical twins were randomly assigned to one of two treatment conditions. One group learned a list of nonsense syllables while a tape of a speech by former President A was playing. The second group learned the same list of syllables while a tape of a speech by President B was playing. The number of presentations of the list before an errorless recital was as follows:

Determine which president’s speech was more distracting and whether or not the difference is significant. Tell what your result means in the context of the problem. Give table values required for significance.