The true count rate of a longlived radioactive source is 316

The true count rate of a long-lived radioactive source is 316 cpm. Background is negligible.

a) What is the expected number of counts in 5 min?

b) What is the standard deviation of the number of counts in 5 min?

c) What is the standard deviation of the count rate obtained from a 5-min count?

Solution

Answer is 0.420