Question

Why do we use standard deviation and not mean to measure the EEG signal?

Select one:

a. Because the standard deviation is easier to measure.

b. Because the standard deviation is less affected by outliers than the mean.

c. Because the standard deviation measures variability and brain signals are more variable than other physiological signals.

d. Because the standard deviation is a better approximation of the mean value of any data.

Answer 1

Answer-C

Standard deviation is the measure of dispersion of a set of data from its mean. It measures the absolute variability of a distribution. The higher the dispersion or variability,the greater is the standard deviation and greater will be magnitude of the deviation of the value from their mean. So, it will be easier to use the standard deviation in EEG signals because the brain signals are variable and standard deviation measures variability. Standard deviation is sensitive to outliers. A single outlier can raise the standard deviation and in turn, distort the picture of spread. Standard deviations are not good or bad. They indicate how spread out the data is. Standard deviation tells us how far , on average the results are from the mean.