Q. 18 The jobs arrive at a facility, for service, in a random manner. The probability distribution of number of arrivals of jobs in a fixed time interval is (A) Normal (C) Erlang (B) Poisson (D) Beta Q. 19 In exponential smoothening method, which one of the following is true? (A) 0 a 1 and high value of a is used for stable demand (B) 0 a (C) a (D) a 1 and high value of a is used for unstable demand 1 and high value of a is used for stable demand 0 and high value of a is used for unstable demand is Q. 21 Which one of the following instruments is widely used to check and calibrate geometric features of machine tools during their assembly? (A) Ultrasonic probe (B) Coordinate Measuring Machine (CMM) (C) Laser interferometer (D) Vernier calipers Q. 22 The major difficulty during welding of aluminium is due to its (A) high tendency of oxidation (C) low melting point (B) high thermal conductivity (D) low density