Exam 7: Sampling and Sampling Distributions

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 uses random five-digits numbers from the website random.org (which offers true random numbers on the Internet).This is an example of ______.

A nonrandom sampling technique which is similar to stratified random sampling is called quota sampling.

If random variable X is distributed according to a uniform distribution between 0 and 1 (X ~ U[0, 1]), and 100 random samples of sizes 35-40 were taken, the sum of the sample means would be ______.

If a researcher wants to study all students in their university and includes only those students in the researcher's class, then the researcher is conducting convenience sampling.

A carload of steel rods has arrived at Cybermatic Construction Company.The car contains 1,000 bundles of 50 rods of various sizes.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 ___.

The sampling distribution of the sample means is less variable than the population distribution.

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 ___.

According to the central limit theorem, if a sample of size 81 is drawn from a population with a standard deviation of 72, the standard deviation of the distribution of the sample means would equal ___.

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 any IP address that accesses the company's website from 8 a.m.to 9 a.m.during each day of the next four weeks.This is an example of ______.

If every unit of the population has the same probability of being selected for the sample, then the researcher is conducting random sampling.

If random variable X is distributed according to a uniform distribution between 0 and 1 (X ~ U[0, 1]), and you take a random sample of size 35, what is the probability that the sample mean will fall between 0.48 and 0.55?

Kristen Ashford purchased the subscribers list for Wind Surfing magazine.She plans to survey a sample of the subscribers before using the list in her mail order business.She chooses the first 100 of the 5,000 names.Her sample is a ___.

If a researcher selects every k^th item from a population of N items, then the researcher is likely conducting a stratified random sampling.

According to the central limit theorem, for samples of size 64 drawn from a population with µ = 800 and σ = 56, the standard deviation of the sample means would equal ___.

Cluster (or area)sampling is a type of random sampling technique.

The directory or map from which a sample is taken is called the frame.

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 ___.

Suppose the population of all public Universities shows the annual parking fee per student is normally distributed with a mean of $110 with a standard deviation of $18.If a random sample of size 49 is drawn from the population, the probability of drawing a sample with a mean of more than $115 is _______.

Nonsampling error occurs when, due to chance, the sample is not representative of the population.

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.If the population of waiting times has a mean of 15 minutes and a standard deviation of 4 minutes, the probability that Albert's sample of 64 will have a mean between 16.5 and 18.5 minutes is ___.