Normality is a behavior that can be normal for an individual (intrapersonal normality) when it is consistent with the most common behavior for that person. Normal is also used to describe individual behavior that conforms to the most common behavior in society (known as conformity). However, normal behavior is often only recognized in contrast to abnormality. In many cases normality is used to make moral judgements, such that normality is seen as good while abnormality is seen as bad, or conversely normality can seen as boring and uninteresting. Someone being seen as normal or not normal can have social ramifications, such as being included, excluded or stigmatized by wider society. Measuring Many difficulties arise in measuring normal behaviors—biologists come across parallel issues when defining normality. One complication that arises regards whether 'normality' is used correctly in everyday language. People say "this heart is abnormal" if only a portion of it is not working correctly, yet it may be inaccurate to include the entirety of the heart under the description of 'abnormal'. There can be a difference between the normality of a body part's structure and its function. Similarly, a behavioral pattern may not conform to social norms, but still be effective and non-problematic for that individual. Where there is a dichotomy between appearance and function of a behavior, it may be difficult to measure its normality. This is applicable when trying to diagnose a pathology and is addressed in the Diagnostic and Statistical Manual of Mental Disorders. Statistical normality In general, 'normal' refers to a lack of significant deviation from the average. The word normal is used in a more narrow sense in mathematics, where a normal distribution describes a population whose characteristics center around the average or the norm. When looking at a specific behavior, such as the frequency of lying, a researcher may use a Gaussian bell curve to plot all reactions, and a normal reaction would be within one standard deviation, or the most average 68.3%. However, this mathematical model only holds for one particular trait at a time, since, for example, the probability of a single individual being within one standard deviation for 36 independent variables would be one in a million. In statistics, normal is often arbitrarily considered anything that falls within about 1.96 standard deviations of the mean, i.e. the most average 95% (1.96). The probability of an individual being within 1.96 standard deviations