Question

1. what does it mean if the results of a study are statistically significant?

a. the null hypothesis can never be rejected in future studies.
b. the sample size was too small to reach a valid conclusion.
c. the study needs to be redesigned and conducted again.
d. the observed effect is unlikely to have occurred by chance, according to the significance level.

Explanation:

Statistical significance means that the observed result is unlikely to be due to random chance. The significance level (e.g., 0.05) is the threshold. If the p - value (probability of the result under the null hypothesis) is less than the significance level, the result is significant.

• Option a: Future studies can reject the null hypothesis. Statistical significance is for the current study, not a guarantee for future ones.
• Option b: A small sample size might affect power (ability to detect an effect), but statistical significance is about the probability of the result under the null, not sample size validity in this context.
• Option c: There is no indication from statistical significance alone that a study needs redesign.
• Option d: This aligns with the definition of statistical significance.

Answer:

d. The observed effect is unlikely to have occurred by chance, according to the significance level.