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.
The charity Cancer Research says that some cancer tumors can cause itching all over the body. Doctors think this could be the bodyâs reaction to the tumor and the itching should go away when treatment starts. 25. Thyroid Problems. According to the National Health Service in the United Kingdom, an overactive or underactive thyroid can cause itchy skin. 26