What does a significance level of 0.05 imply about the results?

A significance level of 0.05 indicates that there is a 5% probability that the observed results occurred due to random chance rather than as a result of the effect being studied. This threshold is commonly used in hypothesis testing to determine whether to reject the null hypothesis. If the p-value calculated from the data is less than 0.05, researchers typically conclude that the results are statistically significant, suggesting that the effect observed is likely genuine and not a product of random variation.

The other choices misinterpret the concept of significance levels. For instance, while it is possible for some results to be statistically insignificant, a significance level of 0.05 itself does not mean there is no significant effect observed. Likewise, not all results can be designated as reliable simply because they fall below the significance threshold; further consideration of practical significance and effect size is essential. Therefore, the correct interpretation of a significance level of 0.05 is that it quantifies the risk of falsely claiming a significant effect when in reality, it could be due to chance.