Radiation Statistics Practice Problems

A radiation detector with 100% counting efficiency obtained ten count measurements, which are all given in the table below. All measurements were acquired using the same conditions. What is the mean value (\mu) for number of counts? Also, given that the radiation statistics follow a normal (Gaussian) distribution, what is the measured standard deviation, both for individual measurements (\sigma_M) and for the mean value (\sigma_{'M})? Finally, what is the theoretical standard deviation, both for individual measurements (\sigma_T) and for the mean value (\sigma_{'T})?