Find the length of stay standard deviation for an inpatient rehab unit based on the following observed encounters. All values are given in days; please round your answer to the nearest hundredth (x.xx) and do not label your response.
{5.60, 5.81, 5.74, 4.30, 8.25, 4.16, 4.51, 5.04, 7.16, 7.15, 7.91, 6.78, 4.19, 6.65, 4.01, 9.06, 10.48, 7.57, 4.50, 4.67}