National data in the 1960s showed that about 44% of the adult population had never smoked cigarettes. In 2004 a national health survey interviewed a random sample of 881 adults and found that 54.6% had never been smokers.

a) Create a 95% confidence interval for the proportion of adults (in 2004) who had never been smokers.

b) Does this provide evidence of a change in behavior among Americans? Using your confidence interval, test an appropriate hypothesis and state your conclusion.