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.
Some cancer treatments cause itching. This may be itching over the whole body (generalised itching) or just in one part of the body. You may also have a rash. Some treatments, such as hormone or biological therapies, can cause an itchy skin rash. This doesnât necessarily mean that you are allergic to the treatment. Researchers have found that for some types of treatment (for example erlotinib) itching can be a sign that your treatment is working.