Refer to the previous question. The results from the 1994 sample of 991 adults were that 91% answered that they were certain the Holocaust happened, 8% did not know, and 1% thought it possible that it never happened.

a. Produce an appropriate graph for comparing the results between the 1992 and 1994 surveys.
b. Summarize how the results diff er between the two surveys.
c. For each survey, determine a 95% confidence interval for the population proportion of American adults who are certain that the Nazi extermination of the Jews happened.

d. Are these confidence intervals similar? Do they overlap?
e. Summarize the lesson to be learned from the two Roper polls.