Final answer:
Variation in data caused by individual fluctuations or patterns is known as special or assignable causes. This type of variation stands in contrast to common causes, which are natural variations, and is different from the standard deviation, which measures the overall spread of data.
Step-by-step explanation:
Variation signaled by individual fluctuations or patterns in the data is called special or assignable causes. The other options provided are related to variability but do not necessarily account for the specific fluctuations or patterns mentioned in the question. Common or chance causes relate to natural variability that affects all processes. Explained variation refers to the portion of variation in the data that can be attributed to specific observable factors. The standard deviation is a measure of the spread of the data, which indicates how much data points deviate from the mean value of the dataset. It can be used to determine whether a particular data value is close to or far from the mean. Special or assignable causes can be identified when data points are outside the expected range dictated by the standard deviation.