Introduction. The standard deviation is a measure of the spread of scores within a set of data. Usually, we are interested in the standard deviation of a population. However, as we are often presented with data from a sample only, we can estimate the population standard deviation from a sample standard deviation.ntroduction. The standard deviation is a measure of the spread of scores within a set of data. Usually, we are interested in the standard deviation of a population. However, as we are often presented with data from a sample only, we can estimate the population standard deviation from a sample standard deviation.
Itching usually results from dry skin, a skin disorder, or an allergic reaction. If the person has no rash or skin abnormalities, the cause may be a drug, an allergic reaction that has internal effects, or a systemic disorder.
Itchy skin can develop for many reasons. It can occur with or without a rash, in small areas or the whole body. Identifying the cause is important to ensure proper treatment. While there are several potential causes of itchy skin, it has not been directly linked to a vitamin B-12 deficiency. However, vitamin B-12 is important to healthy skin and may be a potential treatment for eczema.