Data collected in 2013 by the Behavioral Risk Factor Surveillance System revealed that in the state of New Jersey, 14.7% of whites and 18.8% of blacks were cigarette smokers. Suppose these proportions were based on samples of 11,112 whites and 1916 blacks.
a) Create a 90% confidence interval for the difference in the percentage of smokers between black and white adults in New Jersey.
b) Does this survey indicate a race-based difference in smoking among American adults? Explain, using your confidence interval to test an appropriate hypothesis.
c) What alpha level did your test use?