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.
Pollen & Rashes. In the spring and summer, many people suffer from itchy hives or rashes on the skin after they come into contact with pollen. Pollen is an allergen that affects many people. Tree pollen and pollen from flowers can cause contact dermatitis rashes, or rashes on the skin. People experience allergies from many different spring and summer flowers. The rash often appears as a red, raised rash. Serious rashes can look like blisters or cause the skin to crack.