In this table, the activity means and standard deviations can be entered using the specified units. We will assume counts per minute (cpm) was chosen for this example.
The expected mean and standard deviation for the survey unit and the reference area must be entered.
The total mean is calculated as the Survey Unit Mean minus the Reference Area Mean. In this example, the total mean is: \(1500 - 500 = 1000 \text{cpm}\).
The total standard deviation is the largest of the Survey Unit Standard Deviation and the Reference Area Standard Deviation. In this example, it is 500 cpm.