Question 1

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

Accepted Answer

A) 0.4332 
B) 0.8664 
C) 0.9332 
D) 0.0668

Question 2

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

Accepted Answer

A) 400 
B) 18 
C) 20 
D) 10

Question 3

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

Accepted Answer

A) always zero 
B) always smaller than the population mean 
C) a random variable 
D) exactly equal to the population mean

Question 4

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

Accepted Answer

A) 0.3636 
B) 0.0331 
C) 0.0200 
D) 4.000

Question 5

Parameters are

Accepted Answer

A) numerical characteristics of a sample 
B) numerical characteristics of a population 
C) the averages taken from a sample 
D) numerical characteristics of either a sample or a population

Question 6

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.

Accepted Answer

The answer of A random sample of nine telephone calls...

Question 7

The purpose of statistical inference is to provide information about the

Accepted Answer

A) sample based upon information contained in the population 
B) population based upon information contained in the sample 
C) population based upon information contained in the population 
D) mean of the sample based upon the mean of the population

Question 8

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

Accepted Answer

A) 8.7 and 1.94 
B) 36 and 1.94 
C) 36 and 1.86 
D) 36 and 8

Question 9

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

Accepted Answer

A) the sample is first divided into strata,and then random samples are taken from each stratum 
B) various strata are selected from the sample 
C) the population is first divided into strata,and then random samples are drawn from each stratum 
D) None of these alternatives is correct.

Question 10

Sampling distribution of  Is the

Accepted Answer

A) probability distribution of the sample mean 
B) probability distribution of the sample proportion 
C) mean of the sample 
D) mean of the population

Question 11

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?

Accepted Answer

The answer of Ten percent of the items produced by...

Question 12

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

Accepted Answer

A) 0.5228 
B) 0.9772 
C) 0.4772 
D) 0.0228

Question 13

The set of all elements of interest in a study is

Accepted Answer

A) set notation 
B) a set of interest 
C) a sample 
D) a population

Question 14

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

Accepted Answer

A) only large sample sizes 
B) only small sample sizes 
C) any sample size 
D) only samples of size thirty or greater

Question 15

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?

Accepted Answer

The answer of A random sample of ten examination papers...

Question 16

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

Accepted Answer

A) normal because  Is always approximately normally distributed 
B) normal because the sample size is small in comparison to the population size 
C) normal because of the central limit theorem 
D) None of these alternatives is correct.

Question 17

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

Accepted Answer

A) approximately normal because  Is always approximately normally distributed 
B) approximately normal because the sample size is large in comparison to the population size 
C) approximately normal because of the central limit theorem 
D) normal if the population is normally distributed

Question 18

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?

Accepted Answer

The answer of In a large university,20% of the students...

Question 19

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.

Accepted Answer

The answer of Consider a population of five families with...

Question 20

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?

Accepted Answer

The answer of A department store has determined that 25%...

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

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

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 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