Refer to question 66. Suppose a sample of 30 factories is to be taken. Determine how many factories of each type the company should select when it is using

(a) A proportional allocation.

(b) An optimal allocation, assuming the stratum population standard deviations are identical to the corresponding sample values.

Question 66

A company that operates three different types of factories is interested in the number of defective products produced. The following table gives the results of a sampling study done on the number of defective parts:

(a) Find an estimate of the total number of defective parts, using an unbiased estimation procedure.

(b) Find a 95 % confidence interval for this total.

Transcribed Image Text:

Number of defective parts in factories of Type 1 75 10 12.3 4.7 N ni Si Type 2 90 15 11.5 7.5 Type 3 100 20 16.4 3.4