In general, normal equation can be found out by multiplying every given equation with coefficient of unknown whose normal equation has to be found out. By adding all those equations, complete normal equation can be found out.

The value of E for a single wave length with dual weights can be given as
E = ?*(1/w1 + 1/w2). On substitution, we get
E = 21*(1/6 + 1/2)
E = 14.

The value of most probable value can be obtained by using formula,
M = (V1 + V2 + V3 +V4) / n. On substitution, we get
M = (2.76 + 4.32 + 9.87 + 8.83) / 4
M = 6.45.

It is a primary rule in every surveying method employed. It helps in equal distribution of error which can actually increase rate of output and accuracy of output.

The formula of arithmetic mean can be given as ?V / n, where n indicates number of observed values and V indicates difference of individual with mean of readings.

The presence of unequal weights may be a problem for having a normal equation. In that case, weights are to be multiplied with constants present with variables for obtaining required equation.

The features in laws of accidental errors include tendency of small errors to be more frequent, positive and negative errors with equal frequency and making large errors occurrence impossible.

If equation is multiplied by its own weight n resulting weight will be equal to reciprocal of original weight.
2*(?+ ?) = 47?30?40??, weight = ¹?₂.

The most probable value obtained from unknowns of normal equation helps in determination of direct observations from equal and unequal weights, indirect readings from equal and unequal weights, observations accompanied by condition equation.

The method of correlates is used in case of more complexity. In that case, it involves usage all information available and conditions mentioned so that it provides result regarding problem raised.