Between quarterly$$ audits, a company likes to check on its accounting procedures to address any problems before they become serious. The accounting staff processes payments on about $150$ orders each day. The next$$ day, the supervisor rechecks $10$ of the transactions to be sure they were processed properly.

Question content area bottom

Part $1$

$$a$)$ Propose a sampling strategy for the supervisor.

A$.$

The supervisor uses a sampling strategy that ranks the order by difficulty from $1$ to $150,$ and then selects every $15$ th transaction to examine.

B$.$

The supervisor examines the first $10$ transactions he receives.

C$.$

The supervisor uses a sampling strategy that assigns numbers $001$ to $150$ to each$$ order, then uses random numbers to select $10$ transactions to examine.

D$.$

The supervisor examines the $10$ transactions that took the accounting staff the least amount of time to complete.

Part $2$

$$b$)$ How should that strategy be modified if the company makes both wholesale and retail$$ sales, requiring different bookkeeping$$ procedures?

A$.$

Sample proportionately within each$$ type, wholesale and retail sales. The result would be a stratified random sample.

B$.$

The amount of transactions the supervisor checks would need to be doubled in order to ensure that he spends equal time on wholesale and retail sales. Other than$$ that, the process remains the same.

C$.$

Alternate days for checking wholesale and retail sales. If one day he focuses on$$ wholesale, the next he will focus on retail sales.

D$.$

The strategy should not be modified.