Question

1.) McMillin Assembly has a contract to assemble components for radar systems to be used by the U.S. military. The time required to complete one part of the assembly is thought to be normally distributed, with a mean equal to 30 hours and a standard deviation equal to 4.7 hours. In order to keep the assembly flow moving on schedule, this assembly step needs to be completed in 26 to 35 hours.

Determine the probability of this happening.

Please answer with excel functions.

Answer 1

Solution :

Given that,

mean = = 30

standard deviation = = 4.7

P (26 < x < 35 )

P ( 26 - 30 / 4.7 ) < ( x -  / ) < ( 35 - 30 / 4.7 )

P ( - 4 / 4.7 < z < 5 / 4.7 )

P (-0.85 < z < 1.06 )

P ( z < -1.06 ) - P ( z < -0.85)

Using z table

= 0.8554 - 0.1977

= 0.6577

Probability = 0.6577