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.
A stress rash. Stress may trigger hives, which are very itchy. The presence of red, itchy bumps may be a sign of a stress rash. Since many illnesses are manifested by skin rashes, it is a good idea to get diagnosis of the rash. Stress can cause acne in adults. Oral antihistamines can help eliminate a stress rash.