contraharmonic mean

Noun

• A type of average calculated as the arithmetic mean of the squares of the values divided by the arithmetic mean of the values, ie. $C\; =\; \{\; \{(\; x\_1^2\; +\; x\_2^2\; +\; ...\; +\; x\_n^2)\; \backslash over\; n\; \}\; \backslash over\; \{\; (\; x\_1\; +\; x\_2\; +\; ...\; +\; x\_n\; )\; \backslash over\; n\; \}\; \}\backslash \; or\; \backslash \; C(x\_1,\; x\_2,\; ...,\; x\_n)\; =\{\; \{\; x\_1^2+x\_2^2+...+x\_n^2\}\; \backslash over\; \{x\_1+x\_2+...+x\_n\; \}\}$