When a Proportionate Stratified Sampling Plan Is Used,the Weighted Mean

Multiple Choice

When a proportionate stratified sampling plan is used,the weighted mean formula:

A) should be used to ensure statistical efficiency.
B) should be calculated using the weights represented by the proportions.
C) should not be used.
D) should be used if the sample size is greater than 100.
E) should be used only if time constraints permit.