\( {\upsilon _{rms}} = \sqrt { < {\upsilon ^2} > } \,\,\)

અહી \( < {\upsilon ^2} > \, = \,\frac{{{\upsilon _1}^2 + {\upsilon _2}^2 + {\upsilon _3}^2 + .... + {\upsilon _n}^2}}{n}\,\,\,\,\,\)

\(\therefore {\upsilon _{rms}} = {\left[ {\frac{{{\upsilon _1}^2 + {\upsilon _2}^2 + {\upsilon _3}^2 + .... + {\upsilon _n}^2}}{n}} \right]^{\frac{1}{2}}}\)