Question

A RANDOM SAMPLE OF SIZE 15 HAS SO AS MEAN. THE SUM OP SQUARES OF DEVIATION
TAKEN FROM MEAN IS 130. CAN THIS SAMPL BE REGARDED AS TAKEN FROM THE
POPULATION HAVING 53 AS MEAN?
OBTAIN 95% AND 99% CONFIDENCE LIMIT OF THE MEAN FOR THE POPULATION.​

Answer 1

the positive algebraic number that, when multiplied by itself, equals the number 2. Technically, it is called the principal square root of 2, to distinguish it from the negative number with the same property.

Geometrically the square root of 2 is the length of a diagonal across a square with sides of one unit of length; this follows the Pythagorean theorem. It was probably the first number known to be irrational.[citation needed]

As a good rational approximation for the square root of two, with a reasonably small denominator, the fraction 99/70 (≈ 1.4142857) is sometimes used.

The sequence A002193 in the OEIS consists of the digits in the decimal expansion of the square root of 2, here truncated to 65 decimal places: