Exam 7: Sampling and Sampling Distributions

Suppose 40% of the population of pre-teens have a TV in their bedroom.If a random sample of 500 pre-teens is drawn from the population, then the probability that 44% or more of the pre-teens have a TV in their bedroom is closest to _______.

Sampling errors cannot by determined objectively for nonrandom sampling techniques.

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?

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 _____________.

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.28% of clients are from the healthcare industry, 35% are manufacturing companies, 27% are financial firms, and 7% are construction companies.For this purpose, she gets random five-digits numbers from the website random.org (which offers true random numbers on the Internet).Then she uses these numbers to select 140 random clients from the healthcare sector, 175 from the manufacturing sector, 135 from the manufacturing sector, and 35 from the construction sector.This is an example of ______.

If the population proportion is 0.90 and a sample of size 64 is taken, which is closest to the probability that the sample proportion is more than 0.89?

Suppose a population has a mean of 870 and a variance of 8,100.If a random sample of size 36 is drawn from the population, the probability that the sample mean is between 840 and 900 is closest to _______.

The mean of the sample means is the same as the mean of the population

If the population is normally distributed, the sample means of size n=5 are normally distributed.

According to the central limit theorem, for samples of size 169 drawn from a population with μ = 1,014 and σ = 65, the mean of the sampling distribution of sample means would equal _______.

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 ________________.

A carload of steel rods has arrived at Cybermatic Construction Company.The car contains 50,000 rods.Claude Ong, manager of Quality Assurance, directs his crew to measure the lengths of 100 randomly selected rods.If the population of rods has a mean length of 120 inches and a standard deviation of 0.05 inch, the probability that Claude's sample has a mean between 119.985 and 120.0125 inches is closest to ____________.

Financial analyst Larry Potts needs a sample of 100 securities listed on the New York Stock Exchange.The current issue of the Wall Street Journal has an alphabetical list of the 2,531 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 ____________.

Suppose 40% of the population of pre-teens have a TV in their bedroom.If a random sample of 500 pre-teens is drawn from the population, then the probability that between 36% and 44% of the pre-teens have a TV in their bedroom is closest to _______.

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 13.5 and 16.5 minutes is closest to ________.

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.

Catherine Chao, Director of Marketing Research, needs a sample of households to participate in the testing of a new toothpaste package.She chooses thirty-six of her closest friends.Catherine's sample is a _____________.

Systematic sampling is a type of random sampling technique.

Suppose 40% of all college students have a computer at home and a sample of 64 is taken.Which is closest to the probability that more than 30 of those in the sample have a computer at home?

Suppose a population has a mean of 400 and a standard deviation of 24.If a random sample of size 144 is drawn from the population, the probability of drawing a sample with a mean of more than 404.5 is closest to _______.