Exam 4: Gathering Data

Pinky Bauer, Chief Financial Officer of Harrison Haulers, Inc., suspects irregularities in the payroll system. She knows that 2,500 payroll vouchers have been issued since January 1, 2000, and her staff doesn't have time to inspect each voucher. So, she randomly selects 53 as a starting point and orders her staff to inspect the 53rd voucher and each voucher at an increment of 100 (53, 153, 253, etc.). Her sample is a ___.

A major limitation of nonrandom samples is that they are not appropriate for most statistical methods.

Which one of the following is a reason for conducting a census instead of taking a sample?

Interviewing all members of a given population is known as

Pinky Bauer, Chief Financial Officer of Harrison Haulers, Inc., suspects irregularities in the payroll system. She knows that 2,500 payroll vouchers have been issued since January 1, 2000, and her staff doesn't have time to inspect each voucher. So, she orders her staff to inspect the last 200 vouchers. Her sample is a ___.

Financial analyst Larry Potts needs a sample of 100 securities listed on the New York Stock Exchange. In the current issue of the Wall Street Journal, 2,531 securities are listed in the "New York Exchange Composite Transactions," an alphabetical listing of all securities traded on the previous business day. Larry randomly selects the 7th security as a starting point, and selects every 25th security thereafter (7, 32, 57, etc.). His sample is a ___.

The two major categories of sampling methods are proportionate and disproportionate sampling.

Alice Zhong is the VP of operations at Pearl Financial Services. She wants to measure customer satisfaction after a new website and other changes were introduced a few months ago. For this purpose, she instructs her staff to prepare a questionnaire and send it to the first 200 clients in their alphabetical list of active clients. This is an example of ___.

Abel Alonzo, Director of Human Resources, is exploring employee absenteeism at the Harrison Haulers Plant. Abel knows that absenteeism varies significantly between departments. For example, workers in the wood shop are absent more than those in the tuning department and the size of the departments ranges from 40 to 120 workers. He orders a random sample of 10 workers from each of the six departments. Abel's sample is a ___.

Sampling errors $\textbf{ cannot }$ by determined objectively for nonrandom sampling techniques.

What is the difference between stratified and cluster sampling? If the objective is to increase precision, which method is preferred?

On Saturdays, cars arrive at David Zebda's Scrub and Shine Car Wash at the rate of 80 cars per hour during the ten-hour shift. David wants a sample of 40 Saturday customers to answer the long version of his quality service questionnaire. He randomly selects 9 as a starting point and instructs the crew to select the 9th customer and each customer at intervals of 20 (9, 29, 49, etc.). His sample is a ___.

On Saturdays, cars arrive at David Zebda's Scrub and Shine Car Wash at the rate of 80 cars per hour during the ten-hour shift. David wants a sample of 40 Saturday customers to answer the long version of his quality service questionnaire. He instructs the Saturday crew to select the first 40 customers. His sample is a ___.

In a random sampling technique, every unit of the population has a randomly varying chance or probability of being included in the sample.

Abel Alonzo, Director of Human Resources, is exploring employee absenteeism at the Harrison Haulers Plant. Abel knows that absenteeism varies significantly between departments. For example, workers in the wood shop are absent more than those in the tuning department and the size of the departments ranges from 40 to 120 workers. He orders a random sample of 10% of the workers from each of the six departments. Abel's sample is a ___.

Which one of the following is $\textbf{ not }$ a reason for taking a sample instead of conducting a census?

Catherine Chao, Director of Marketing Research, needs a sample of households to participate in the testing of a new toothpaste package. She directs the seven members of her staff to find five households each. Catherine's sample is a ___.

A carload of steel rods has arrived at Cybermatic Construction Company. The car contains 1,000 bundles of 50 rods each. Claude Ong, manager of Quality Assurance, directs the receiving crew to deliver the 63rd and 458th bundles to his crew for 100% inspection. Claude randomly selected 63 and 458 from a table of random numbers. Claude's sample of 100 rods is a ___.

In some situations, sampling may be the only option because the population is inaccessible.

Albert Abbasi, VP of Operations at Ingleside International Bank, is evaluating the service level provided to walk-in customers. Accordingly, he plans a sample of waiting times for walk-in customers. Albert instructs his staff to record the waiting times for the first 45 walk-in customers arriving after the noon hour. Albert's sample is a ___.