The standard deviation of a random variable, statistical population, data set, or probability distribution is the square root of its variance. It is algebraically simpler, though in practice less robust, than the average absolute deviation.he variance is the mean of these values: and the population standard deviation is equal to the square root of the variance: This formula is valid only if the eight values with which we began form the complete population.
Report Abuse. 1  Sounds like the sweep worked. You will typically go into labor within 24-48 hours if a membrane sweep worked. 2  For some it doesn't work at all - if its going to work usually within 24hrs you are in labor. Invisible Pink RN Â· 7 years ago.
A membrane (cervical) sweep is a vaginal examination during which your midwife will use her finger to sweep the neck of your womb to try to separate the membranes from your cervix (don't try this at home).Related links. 1  Early stage of labour.ometimes, despite trying all the alleged means of getting labour going naturally, your due date is replaced by an overdue date. Your midwife and the obstetric team may then want to up the ante and try to get labour started with medical interventions, such as a membrane sweep.