Can anyone list me any 2 advantages standard deviatihas over range as a measure of spread of data?
One thing I know is that range is not a good measure because it is easily affected by extreme values.
Thanks.
This is a good question. You have listed the most important point.
Standard deviation makes use of all data to calculate the spread of data from average while range only uses two data ie the largest value data and the smallest value data, so standard deviation is a more accurate measure.
In addition, standard deviation measures the spread of data from the MEAN while range measures only the two extreme values ie the difference between the largest value and smallest value data.
Thirdly, standard deviation can be used in the statistical analysis eg hypothesis testing.
Fourthly, standard deviation gives weightage to the deviation of the data from the mean by squaring it ie the greater the deviation, the greating the weightage after the squaring.
Fifthly, standard deviation gives weightage to the positive and negative deviation of the data from the mean too.
Hence, Standard deviation is a more precise measure of spread of data as compared to the rudimentary range measure of the spread of data.