15. An auditor for the state highway and safety department needs to estimate the average highway weight of tractor-trailer trucks using the state's highway system. Which estimation method must be used?
A. Mean-per-unit.
B. Difference.
C. Ratio.
D. Probability-proportional-to-size
ANSWER (A) is correct.
REQUIRED: The best sampling estimation method to estimate an average weight.
DISCUSSION: Mean-per-unit sampling estimates the average value of population items, in this case, truck weight.
Answer (B) is incorrect. Difference estimation compares recorded and audit amounts. Recorded amounts are not relevant to the current procedure.
Answer (C) is incorrect. Ratio estimation compares recorded and audit amounts. Recorded is amounts are not relevant to the current procedure.
Answer (D) is incorrect. Probability-proportional-to-size estimation compares recorded and audit amounts. Recorded amounts are not relevant to the current procedure.