Usually the decay is said to be randomly but the average period of decay of certain atoms are stable. So if you randomly take a bunch of the same atoms the average time before the decay will fe be 5 days.
But imagine that you could create a bunch of atoms at the same time by decaying uranium atoms. Imagine that you succeeded in creating at the same time a buch of polonium atoms. So they all have the same age. Is the time that those polonium atoms decays in lead also has the same variety of decay with a certain average time or are all polonium atoms decaying more or less at the same time?
Perhaps uranium is not a good example, but it is about the principle question.
To make a distinction of other questions: when atoms are created is there a difference is spreading decay time among those atoms or is the spread of decay time the same, although of course the average time would stay the same?
