Question

What does statistical significance really mean?

Answer 1

Statistical significance is the likelihood that a relationship between two or more variables is caused by something other than chance.

Statistical significance is used to provide evidence concerning the plausibility of the null hypothesis, which hypothesizes that there is nothing more than random chance at work in the data.

Statistical significance is a determination about the null hypothesis, which hypothesizes that the results are due to chance alone.

In principle, a statistically significant result (usually a difference) is a result that’s not attributed to chance.

More technically, it means that if the Null Hypothesis is true (which means there really is no difference), there’s a low probability of getting a result that large or larger.

Significance also does not quite tell us the probability of the result we got (or one more extreme) if the hypothesis is true. It just tells us an upper bound on the probability of false "rejections."

Example:-We say that  Average weight for People in India is 55 kg.

we found that the average weight people in Delhi is 57 kg.

As we can see that average weight of Delhi people is different from then national average weight.

so in practice, we say that both have different weights.

but by doing a statistical hypothesis test we confirm that there is really significant difference in weight.

the weights are really different or it is due to some random chance.

summary:

Statistical significance is a determination about the null hypothesis, which hypothesizes that the results are due to chance alone.