本人初学统计学，教材是英文，无奈英语较弱，盼哪位牛人能读懂以下句子，告知一二。谢谢！！！

“A statistically significant relationship or difference is one that is large enough to be unlikely to have occurred in the sample if there was no relationship or difference in the population.”句中的large enough到底是什么意思？“总体中没有差异，样本中就没有差异，那差异又怎么会足够大呢？”