Usually, however, there is some correlation between these variables, which reduces the reliability of natural experiments relative to what could be concluded if a controlled experiment were performed.
Harkuk, aguden, eɣlaqkid amərtay iyan jar imətuyan, awen ifanazan assuhu ən iruman iknanen ye awa adoben oɣəl ən samdo as irum atiwakiyadan eqal ayjan