these are the four different symbols that have been used to represent specific statistical measures like for example, mean which is used to calculate the average value of a sample or population. Variance is the what is expected from the squared standard deviation of a random variable from is average vale/ mean. Median is the value that lies in the middle in a random sample and lastly the standard deviation is the square root of the variance and it measures how the values of sample are spread or how far are they from the mean. these are also commonly use in excel a lot to calculate and evaluate data.
