âº EVC System. A disabled refuge is a relatively safe area within a building or exit staircase for mobility impaired occupants, allowing building management and emergency services to safely assist these people from the building.
Standard deviation is a number used to tell how measurements for a group are spread out from the average (mean), or expected value. A low standard deviation means that most of the numbers are very close to the average. A high standard deviation means that the numbers are spread out.
Simply put, the standard deviation is a measure of the spread of the sample from the mean. As a rule of thumb, about 2/3 of a sample is within 1 standard deviation from the mean. About 95% of the sample will be within 2 standard deviations from the mean (3).