A p-value of 0.04 indicates what, assuming a typical alpha of 0.05?

• A. The result is not statistically significant at the 0.05 level.
• B. It is incorrect to interpret p-values this way.
• C. Interpretation of p-values does not depend on the chosen alpha level.
• D. Assuming a typical alpha of 0.05, the result is statistically significant; the probability of observing such data if the null is true is 4%.

Answer: (D)

The main idea is that the p-value measures how compatible the observed data are with the null hypothesis. A p-value of 0.04 means that, if there is no true effect, such an extreme result would occur about 4% of the time. Because this is below the typical alpha level of 0.05, you reject the null at that threshold and call the result statistically significant. It’s important to note that the p-value does not say the probability that the null is true; it reflects the rarity of the observed data under the assumption of no effect. If the p-value were larger than 0.05, you would not declare significance at that level.