1 A batch of 30 semiconductor chips is inspected by choosing

1) A batch of 30 semiconductor chips is inspected by choosing a sample of 4 chips. Assume 10 of the chips do not conform to customer requirements. Round your answers to the nearest integer.

a. How many different samples are possible?

b. How many samples of 4 contain exactly one nonconforming chip? c. How many samples of 4 contain at least one nonconforming chip?

c. How many samples of 4 contain at least one nonconforming chip?

STATISTICS 510

2) A manufacturing operations consists of 14 operations. However, five machining operations must be completed before any of the remaining assembly operations can begin. Within each of these two sets, operations can be completed in any order. How many different production sequences are possible?

STAT 510

Solution

a)

no of different samples = 30C4 = 27405

b)

3 good and one bad

no of samples = 20C3 * 10C1 = 11400

c)

3 good one bad + 2 good 2 bad + 1 good 3 bad + 4 bad

no of samples = 20C3 * 10C1 + 20C2 *10C2 + 20C1 * 10C3 + 10C4

= 22560