Increasing the frequency of observations in the tails of a distribution will increase the standard deviation because the data points are added once observations are made. In this case, the data points may be attributed to more error that increases the separation between data points.
Because tha data placed in the tail of the distribution is the most separated data from the central stats, so, variation measures will be affected if we increase the representation of the least central values.
Remember that the standard deviation represents the degree of deviation regarding the mean is the data. So, if we increase data in the tails, we will increase the most ranged data, so the variation will be higher, which means the standard deviation will also increase.
