When are conclusions said to be statistically significant?

If the p-value is less than a given significance level, you reject the null hypothesis and accept the alternative hypothesis.

Step-by-step explanation:

Suppose you have a business in which you'd like to make a change to increase your business. After making the change, you can use a significance test it. To conduct a significance test, you make a null hypothesis which states essentially that no effect happened. You also make an alternative hypothesis that states the change had an effect. You then test the two to see which one stands. In a significance test, using the p-value from your sample you compare it to the null and alternative hypotheses. You make a conclusion when:

If the p-value is less than a given significance level, you reject the null hypothesis and accept the alternative hypothesis since the evidence is in favor of it.

If the p-value is greater than the significance level, then you fail to reject the null hypothesis and cannot conclude. There isn't evidence in favor of the alternative hypothesis.