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.
Allergens that cause symptoms to stick around a lot longer, or to come back, are much harder to pinpoint. Itâs important to know the allergens that could cause a flare up, so that you can help keep your rash under control. Hormones. Hormones are substances produced by the body that can cause a wide variety of symptoms. When the levels of certain hormones in your body increase or decrease, some people with eczema (especially women) may experience flare ups. Learn more about how to control the most common eczema causes and triggers. Home.