Refer to question 78. Suppose a sample of 50 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 78

A company operating three factories that use different types of production 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 90 % confidence interval for this total.

Transcribed Image Text:

Number of defective parts in production of Type 1 55 12 Ni ... N ni xi si 22.3 10.7 Type 2 9 35.4 9.5 Type 3. 150 40 26.3 13.4