Exam 7: Sampling and Sampling Distributions

A population has a mean of 300 and a standard deviation of 18.A sample of 144 observations will be taken.The probability that the sample mean will be between 297 to 303 is

A simple random sample of 5 observations from a population containing 400 elements was taken,and the following values were obtained. A point estimate of the mean is

If we consider the simple random sampling process as an experiment,the sample mean is

Exhibit 7-1 A random sample of 121 bottles of cologne showed an average content of 4 ounces.It is known that the standard deviation of the contents (i.e. ,of the population)is 0.22 ounces. -Refer to Exhibit 7-1.The standard error of the mean equals

Parameters are

A random sample of nine telephone calls in an office provided the following information. a.Determine the point estimate for the average duration of all calls. b.What is the point estimate for the standard deviation of the population? c.Determine the standard error of the mean. d.What is the point estimate for the proportion of all calls that were long distance? e.Determine the standard error of proportion.

The purpose of statistical inference is to provide information about the

Random samples of size 17 are taken from a population that has 200 elements,a mean of 36,and a standard deviation of 8.The mean and the standard deviation of the sampling distribution of the sample means are

Stratified random sampling is a method of selecting a sample in which

Sampling distribution of Is the

Ten percent of the items produced by a machine are defective.A random sample of 100 items is selected and checked for defects. a.Determine the standard error of the proportion. b.What is the probability that the sample will contain more than 2.5% defective units? c.What is the probability that the sample will contain more than 13% defective units?

A population has a mean of 80 and a standard deviation of 7.A sample of 49 observations will be taken.The probability that the sample mean will be larger than 82 is

The set of all elements of interest in a study is

Whenever the population has a normal probability distribution,the sampling distribution of Is a normal probability distribution for

A random sample of ten examination papers in a course that was given on a pass or fail basis showed the following scores. a.What is the point estimate for the mean of the population? b.What is the point estimate for the standard deviation of the population? c.What is the point estimate for the proportion of all students who passed the course?

A sample of 92 observations is taken from an infinite population.The sampling distribution of Is approximately

A sample of 24 observations is taken from a population that has 150 elements.The sampling distribution of Is

In a large university,20% of the students are business majors.A random sample of 100 students is selected,and their majors are recorded. a.Compute the standard error of the proportion. b.What is the probability that the sample contains at least 12 business majors? c.What is the probability that the sample contains less than 15 business majors? d.What is the probability that the sample contains between 12 and 14 business majors?

Consider a population of five families with the following data representing the number of pets in each family. a.Determine the mean and the variance of the population. b.There are ten possible samples of size 2 (sampling without replacement).List the 10 possible samples of size 2,and determine the mean of each sample. c.Using the ten sample mean values,compute the mean and the standard error of the mean.

A department store has determined that 25% of all their sales are credit sales.A random sample of 75 sales is selected. a.What is the probability that the sample proportion will be greater than 0.34? b.What is the probability that the sample proportion will be between 0.196 and 0.354? c.What is the probability that the sample proportion will be less than 0.25? d.What is the probability that the sample proportion will be less than 0.10?