**1.**Theory of probability is applied to

**accidental errors.**

**2.**Most probable value of an observed quantity available from a given set of observation is the one for which the sum of the square of errors is a minimum. This statement is called

**principle of least square.**

**3.**For a measured distance L along a slope, the required slope correction is

**2L.[sin(A/2)]^2.**

**4.**A 30 m chain was found to be 20 cm too long after chaining 1500 m. Correct length of the total distance chained will be

**1510 m.**

**5.**If n observations are taken then the accidental errors are proportional to

**n^(1/2)**.

**6.**If a chain is found too short on testing then it can be adjusted by

**straightening the links, inserting additional circular links and flattening the circular rings.**

**7.**Permissible limits of error in chaining for measurement on rough or hilly ground is

**1:250**

**8.**Position of point can be fixed more accurately by

**perpendicular offset.**

**9.**Positive error is caused if

*length of chain is shorter than standard, slope and sag corrections in not applied and measurements are made along the incorrectly aligned line.*

**10.**If during a chain survey along a straight line, leader of the survey party has three arrows and while follower has five arrows, then distance of the follower from the starting point is

**Five chains.**

*Reference: GK publishers*