A number of school boys were examined for the presence or absence of the three physical defectives, viz., development defect denoted by A, nerve signs denoted by B and low nutrition denoted by C. Following data in terms of the ultimate class frequencies were observed: (ABC)- 149, (ABY) -738, (APC) -225, (Aß7) - 1196, (CIBC)- 204 (aBy) — 1762, (UPC) — 171 and (uh')— 21842. Find all the class frequencies which are for the presence of defects.

The first four moments Of a distribution about the value 4 of the variable are —l .5, 17, —30 and 108. Find the moments about mean, and Find also the moments about

(i) the origin, and

(ii) the point x 2.

In a very hotly fought battle atleast 70% of the combatants lost an eye, atleast 75% lost an ear, atleast 80% lost an arm and atleast 85% lost a leg. How many atleast must have lost all four?

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