formula for calculating variance

To calculate the confidence interval for variance or standard deviation, a statistical distribution called ______ is needed. => chi-square distribution or binomial distribution or poisson distribution or multinomial distribution..

Let, The mass of the organic compound taken be = W g Increase in the mass of magnesium perchlorate tube = W 1 g Increase in the mass of the KOH tube = W 2 g So, Mass of water formed = W 1 g Mass of carbon dioxide formed = W 2 g ..

Let, The mass of the organic compound be = W g Mass of the precipitate of BaSO 4 = W 1 g From stoichiometry, BaSO 4 = S 1 mol 1 mol 1 molecular mass 1 atomic mass 233 g 32 g Therefore, ..

Let, The mass of silver salt taken for ignition be = W g Mass of silver left behind after ignition = W 1 g We have RCOOAg = Ag1 equivalent 1 equivalent The equivalent mass of silver is 108. Hence, the mass of silver salt that would leave 108 g of residue (equivalent mass of the silver) i..

Let, The mass of the organic compound taken be = W g Volume of air displaced = V 1 mL Atmospheric pressure = P mm of Hg Room temperature, T 1 = t o C = (t + 273)K Aqueous tension at t o C = p mm of Hg Pressure of the dry air, P 1 = (P-p) mm Hg ..

Let, The mass of the organic compound taken be = W g Volume of nitrogen collected = V 1 g Atmospheric pressure = P mm Hg Temperature at which gas is collected = T 1 K Therefore, Pressure of the N 2 gas, P 1 = (P - p) mm of Hg ..

If X is a discrete random variable then variance of X denoted by V(X) is defined as V(X) = E [X - E(X)] 2 V(X) = E(X 2 ) - [E(X)] 2 ..

We have = n(n-1) p 2 (p+q) n - 2 + np = n 2 p 2 - np 2 + np = n 2 p 2 + np(1-p) = n 2 p 2 + npq Now V(x) = E(x 2 ) - [E(x)] 2 = n 2 p 2 + npq - n 2 p 2 = n..

Calculate empirical formula Use vapour density if given If molecular weight given, calculate 'n' using this formula Molecular formula = n x empirical formula..

Knowing the solubility product of a sparingly soluble salt like AgCl, PbI 2 , BaSO 4 etc. the solubility of the salt can be calculated..