The dental hygienists’ hypothesis that there is no significant correlation between cigarette smoking and oral lesions is an example of which type of hypothesis?

• A. Null
• B. Alternative
• C. Directional
• D. Correlational

Answer: (A)

The claim that there is no significant correlation between cigarette smoking and oral lesions is a null hypothesis. It asserts that there is no relationship between the two variables (often written as no correlation, ρ = 0), and the study uses data to test whether that assumption can be rejected. If the data show a significant relationship, the alternative hypothesis would be that a correlation exists (ρ ≠ 0, or a specified direction). A directional hypothesis would state whether the correlation is positive or negative, which isn’t specified here. “Correlational” describes the type of study, not the hypothesis form, so it’s not the best label for the hypothesis.