A Gallup Poll found that of 800 randomly selected drivers surveyed, 70% thought they were better-than-average drivers. In truth, in the population, no more than 50% of all drivers can be “better than average,” assuming “average” is equivalent to the median level of skill. 

a. Draw a picture of the possible sample propor­tions that would result from samples of 800 people from a population with a true propor­tion of .50.

b. Would we be unlikely to see a sample proportion of .70, based on a sample of 800 people, from a population with a proportion of .50? Explain, using your picture from part (a).

c. Which one of the psychological issues discussed in Chapter 16 would help explain the results of this survey?