Are you able to predict precisely the count rate for a radioactive material?
Why or why not?
Depends upon how much you know about the radioactive material and how much you know about the instrument and how it is being used. Also depends upon what you mean by "precisely."
You can only know the number of counts as accurately as probability allows. A highly radioactive substance will be more accurate over a given amount of time than a lesser radioactive substance simply due to the greater amount of decays that the first substance undergoes in that period of time.
A 'random' process cannot be predicted 'precisely' (i.e. zero error). However, if you specify the required precision, then you can say (approximately) how many events would need to be known in order to reach that (order of) precision.
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