Question

According to the Centers for Disease Control and Prevention, the proportion of U.S. adults age 25 or older who smoke is .22. A researcher suspects that the rate is lower among U.S. adults 25 or older who have a bachelor's degree or higher education level. What is the null hypothesis in this case?

a. The proportion of smokers among U.S. adults 25 or older who have a bachelor's degree or higher is less than 0.22.
b. The proportion of smokers among U.S. adults 25 or older who have a bachelor's degree or higher is 0.22.
c. The proportion of smokers among U.S. adults 25 or older who have a bachelor's degree or higher is not 0.22.
d. There is no relationship between education level and smoking habits.

Answer 1

b. The proportion of smokers among U.S. adults 25 or older who have a bachelor's degree or higher is 0.22.

Explanation:

The null hypothesis (H0) tries to show that no significant variation exists between variables or that a single variable is no different than its mean.

While an alternative Hypothesis (Ha) attempt to prove that a new theory is true rather than the old one. That a variable is significantly different from the mean.

Therefore, for the case above, the null hypothesis is that the proportion of smokers among U.S. adults 25 or older who have a bachelor's degree or higher is 0.22.

Answer 2

Answer: d. There is no relationship between education level and smoking habits.

Explanation:

The null hypothesis is the affirmation that two parameters or phenomena do not have a relation between them.

Here the parameters are smoking and having a bachelor's degree or higher education.

Then the null hypothesis says that those two things do not have any relation, this would imply that the probability of being a smoker does not depend on having a degree or not.

Then the correct option is d "There is no relationship between education level and smoking habits."