List of top Mathematics Questions on Statistics asked in JKCET

For a frequency distribution, the mean deviation about the mean is computed by
If $ {{x}_{1}},{{x}_{2}},......{{x}_{18}} $ are observations such, that $ \sum\limits_{j=1}^{18}{({{x}_{j}}-8)=9} $ and $ \sum\limits_{j=1}^{18}{{{({{x}_{j}}-8)}^{2}}=45,} $ then the standard deviation of these observations is
The standard deviation of the first n natural numbers is