Exam 7: Sampling and Sampling Distributions

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

According to the central limit theorem,if a sample of size 100 is drawn from a population with a mean of 80,the mean of all sample means would equal ___.

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

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 ___.

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 ___.

Suppose a population has a mean of 90 and a standard deviation of 28.If a random sample of size 49 is drawn from the population,the probability of drawing a sample with a mean of more than 95 is ___.

According to the central limit theorem,if a sample of size 64 is drawn from a population with a standard deviation of 80,the standard deviation of sample means would equal ___.

Describe the distribution of a sample's proportion using the z formula for sample proportions.

Financial analyst Larry Potts needs a sample of 100 securities listed on either the Toronto Stock Exchange (TSX)or the New York Stock Exchange (NYSE).According to the Report on Business Magazine's "Stock Market Data Bank," 2,531 TSX securities and 746 NYSE securities were traded on the previous business day.Larry directs his staff to randomly select 77 TSX and 23 NYSE securities.His sample is a ___.

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 randomly selects the fourth name as a starting point and then selects every 50th subsequent name (54,104,154,etc. ).Her sample is a ___.

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' sample is a ___.

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 ___.

Suppose a population has a mean of 90 and a standard deviation of 28.If a random sample of size 49 is drawn from the population,the probability of drawing a sample with a mean of less than 84 is ___.

A sampling distribution is the distribution of a sample statistic such as the sample mean or sample proportion.

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 randomly selects 4 as a starting point and instructs his staff to record the waiting times for the 4th walk-in customer and every 10th customer thereafter (4,14,24,etc. ).Albert's sample is a ___.

Increasing the sample size causes the numerical value of the standard error of the mean to increase.