According to the centers for disease control and prevention, the proportion of u. s. adults age 25 or older who smoke is 0.22. a researcher suspects that the rate is lower among u. s. adults 25 or older who have a bachelor's degree. she took a random sample of 275 u. s. adults 25 or older who have a bachelor's degree, and the proportion of smokers in her sample is 0.18. what is the null hypothesis in this case? what is the alternative hypothesis in this case?