Exam 7: Sampling and Sampling Distributions

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

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

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

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 ___.

Financial analyst Larry Potts needs a sample of 100 securities listed on the Toronto Stock Exchange.In the current issue of the Report on Business Magazine,2,531 securities are listed in the "Toronto Exchange Composite Transactions," an alphabetical listing of all securities traded on the previous business day.Larry uses a table of random numbers to select 100 numbers between 1 and 2,531.His sample is a ___.

The standard deviation of a sampling distribution of the sample means is commonly called the standard error of the mean.

Suppose a population has a mean of 450 and a variance of 900.If a random sample is size 100 is drawn from the population,the probability that the sample mean is between 448 and 453 is ___.

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

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 between 85 and 95 is ___.

Increasing the sample size causes the sampling distribution of to ___.

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

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 carload of palletized aluminum castings has arrived at Mansfield Motor Manufacturers.The car contains 1,000 pallets of 100 castings each.Mario Munoz,manager of Quality Assurance,directs the receiving crew to deliver the 127th and 869th pallets to his crew for 100% inspection.Mario randomly selected 127 and 869 from a table of random numbers.Mario's sample of 200 castings is a ___.

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

Catherine Chao,Director of Marketing Research,needs a sample of Ottawa households to participate in the testing of a new toothpaste package.If 40% of the households in Ottawa prefer the new package,the probability that Catherine's random sample of 300 households will have a sample proportion between 0.35 and 0.45 is ___.

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 less than 402 is ___.

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 ___.

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 between 395.5 and 404.5 is ___.

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 ___.

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