Question 1

The probability is 0.22 that the sample mean will be more than what value?

Accepted Answer

P(   
> a)= 0.22 ⇒ P   
= 0.22
⇒ P   
= 0.22
⇒   = 0.77 ⇒ a = 567.94

Question 2

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
You have recently joined a country club.Suppose that the number of times you expect to play golf in a month is represented by a normally distributed random variable with a mean of 10 and a standard deviation of 2.4.
-Over the course of the next year,what is the probability that you average more than 11 games a month?

Accepted Answer

μ = 10,σ = 2.4,n = 12
P(   > 11)= P(Z > 1.44)= 1 - 0.9251 = 0.0749

Question 3

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Suppose that 20% of all invoices are for amounts greater than $800.A random sample of 50 invoices is taken.
-Suppose that 15% of all invoices are for amounts greater than $1,000.A random sample of 60 invoices is taken.What is the probability that between 13% and 23% of these 60 invoices are for more than $1,000?

Accepted Answer

A) 0.4591 
B) 0.2019 
C) 0.1664 
D) 0.6255 
A) 0.4591 
B) 0.2019 
C) 0.1664 
D) 0.6255 D

Question 4

Which of the following statements is true regarding the standard error of the mean?

Accepted Answer

A) It is equal to the population variance divided by the square root of n. 
B) It is equal to the population standard deviation divided by the sample size n. 
C) It is equal to the population variance divided by (n -1). 
D) It is equal to the population standard deviation divided by the square root of n. 
A) It is equal to the population variance divided by the square root of n. 
B) It is equal to the population standard deviation divided by the sample size n. 
C) It is equal to the population variance divided by (n -1). 
D) It is equal to the population standard deviation divided by the square root of n.

Question 5

List all possible samples of 2 families that can be selected without replacement from this population,and compute the sample mean for each sample.

Accepted Answer

The answer of List all possible samples of 2 families...

Question 6

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Given a population with mean μ=120 and variance σS1U1P12S1S1P0 = 81,the central limit applies when the sample size is large-enough.A random sample of size n = 36 is obtained.
-What is the probability that the sample mean is between 118 and 121?

Accepted Answer

P(118 ≤ @#IMG-DLM& ≤ 121)= P(-

Question 7

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
In a recent survey of high school students,it was found that the average amount of money spent on entertainment each week was normally distributed with a mean of $52.30 and a standard deviation of $18.23.Assume that these values are representative of all high school students.
-The probability is 65% that the average spending of a sample of 25 randomly-selected students will spend at least how much?

Accepted Answer

P( @#IMG-DLM& 
≥ a)= 0.65 ⇒ P(

Question 8

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Given a population with mean μ=120 and variance σS1U1P12S1S1P0 = 81,the central limit applies when the sample size is large-enough.A random sample of size n = 36 is obtained.
-What is the probability that the sample mean is at most 121.5?

Accepted Answer

P( @#IMG-DLM& ≤ 121.

Question 9

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
According to the Internal Revenue Service,80% of all tax returns lead to a refund.A random sample of 100 tax returns is taken.
-What is the standard error of the sample proportion?

Accepted Answer

The answer of THE NEXT QUESTIONS ARE BASED ON THE...

Question 10

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
You have recently joined a Weight Watchers club.Suppose that the number of times you expect to visit the club in a month is represented by a normally distributed random variable with a mean of 12 and a standard deviation of 2.50.
-The probability is 85% that you average less than how many visits to the club per month over the course of next year?

Accepted Answer

A) 12.75 
B) 11.50 
C) 12.50 
D) 11.75 
A) 12.75 
B) 11.50 
C) 12.50 
D) 11.75

Question 11

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Times spent studying by students in the week before final exams follow a normal distribution with standard deviation 9 hours.A random sample of 5 students was taken in order to estimate the mean study time for the population of all students.
-What is the probability that the sample mean differs from the population mean by ± 4.1 hours?

Accepted Answer

P(-4.1 < @#IMG-DLM& - μ < 4.1)

Question 12

The chi-square family of distributions is used in applied statistical analysis because it provides a link between the sample and population variances.

Accepted Answer

A) True 
 B)False

Question 13

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A random sample of size n = 25 is obtained from a normally distributed population with population mean μ = 200 and variance σS1U1P12 S1S1P0= 100.
-What is the probability that the sample mean is greater than 203?

Accepted Answer

P( @#IMG-DLM& > 203)

Question 14

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Candidates for employment at a city fire department are required to take a written aptitude test.Scores on this test are normally distributed with mean 260 and standard deviation 51.A random sample of nine test scores was taken.
-What is the probability that the sample mean score is more than 230?

Accepted Answer

P( @#IMG-DLM& > 230)

Question 15

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
In taking a sample of n observations from a population of N members,the variance of the sampling distribution of the sample means is   
=   
   
.The quantity   
is called the finite population correction factor.
-Explain why the result for possible magnitudes of the finite population correction factor,for samples of n =15 observations from populations of N = 15,30,60,100,500,1,000,5,000,and 10,000 members,is precisely what one should expect on intuitive grounds.

Accepted Answer

When the population size (N)equals the s

Question 16

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A sample of 25 bottles is taken from the production line at a local bottling plant.Assume that the fill amounts follow a normal distribution.
-The length of time it takes a stock analyst to complete an evaluation of a company's earnings forecast is normally distributed with a mean of 6.7 hours.From looking at the time spent by an analyst evaluating 36 randomly selected stocks you find that the sample mean was 6.4 hours.If you are told that the probability of getting a sample mean this small or smaller is 0.10,what must the population standard deviation have been?

Accepted Answer

P( @#IMG-DLM& 
< 6.4)= 0.10 ⇒

Question 17

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Given a population with mean μ=120 and variance σS1U1P12S1S1P0 = 81,the central limit applies when the sample size is large-enough.A random sample of size n = 36 is obtained.
-What is the probability that the sample mean is greater than 123?

Accepted Answer

P( @#IMG-DLM& > 123)

Question 18

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A store has determined that 28% of all refrigerators purchasers will also purchase a service agreement.In one month,250 refrigerators are sold to customers who can be regarded as a random sample of all purchasers.
-What are the mean and standard error of the sampling distribution for the proportion of those who will purchase a service agreement?

Accepted Answer

E( @#IMG-DLM& 
)= P

Question 19

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
The filling machine at a bottling plant is operating correctly when the variance of the fill amount is equal to 0.3 ounces.Assume that the fill amounts follow a normal distribution.
-What is the probability that for a sample of 30 bottles,the sample variance is greater than 0.5?

Accepted Answer

P(s² > 0.5)= P @#IMG-DLM& = P(χ² > 48.33)

Question 20

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
It has been found that 62.1% of all unsolicited third class mail delivered to households goes unread.Over the course of a month,a household receives 100 pieces of unsolicited mail.
-What is the probability that the sample proportion is greater than 0.60?

Accepted Answer

P( @#IMG-DLM& > 0.60

The probability is 0.22 that the sample mean will be more than what value?

Which of the following statements is true regarding the standard error of the mean?

List all possible samples of 2 families that can be selected without replacement from this population,and compute the sample mean for each sample.

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: Given a population with mean μ=120 and variance σ² = 81,the central limit applies when the sample size is large-enough.A random sample of size n = 36 is obtained. -What is the probability that the sample mean is between 118 and 121?

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: Given a population with mean μ=120 and variance σ² = 81,the central limit applies when the sample size is large-enough.A random sample of size n = 36 is obtained. -What is the probability that the sample mean is at most 121.5?

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: According to the Internal Revenue Service,80% of all tax returns lead to a refund.A random sample of 100 tax returns is taken. -What is the standard error of the sample proportion?

The chi-square family of distributions is used in applied statistical analysis because it provides a link between the sample and population variances.

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: A random sample of size n = 25 is obtained from a normally distributed population with population mean μ = 200 and variance σ²= 100. -What is the probability that the sample mean is greater than 203?

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: Given a population with mean μ=120 and variance σ² = 81,the central limit applies when the sample size is large-enough.A random sample of size n = 36 is obtained. -What is the probability that the sample mean is greater than 123?

Describing Data: Graphical

Describing Data: Numerical

Probability

Discrete Random Variables and Probability Distributions

Continuous Random Variables and Probability Distributions

Estimation: Single Population

Estimation: Additional Topics

Hypothesis Testing: Single Population

Hypothesis Testing: Additional Topics

Simple Regression

Multiple Regression

Additional Topics in Regression Analysis

Analysis of Categorical Data

Analysis of Variance

Time-Series Analysis and Forecasting

Additional Topics in Sampling

Filters

Exam 6: Sampling and Sampling Distributions

The probability is 0.22 that the sample mean will be more than what value?

Which of the following statements is true regarding the standard error of the mean?

List all possible samples of 2 families that can be selected without replacement from this population,and compute the sample mean for each sample.

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: Given a population with mean μ=120 and variance σ2 = 81,the central limit applies when the sample size is large-enough.A random sample of size n = 36 is obtained. -What is the probability that the sample mean is between 118 and 121?

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: Given a population with mean μ=120 and variance σ2 = 81,the central limit applies when the sample size is large-enough.A random sample of size n = 36 is obtained. -What is the probability that the sample mean is at most 121.5?

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: According to the Internal Revenue Service,80% of all tax returns lead to a refund.A random sample of 100 tax returns is taken. -What is the standard error of the sample proportion?

The chi-square family of distributions is used in applied statistical analysis because it provides a link between the sample and population variances.

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: A random sample of size n = 25 is obtained from a normally distributed population with population mean μ = 200 and variance σ2 = 100. -What is the probability that the sample mean is greater than 203?

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: Given a population with mean μ=120 and variance σ2 = 81,the central limit applies when the sample size is large-enough.A random sample of size n = 36 is obtained. -What is the probability that the sample mean is greater than 123?

Describing Data: Graphical

Describing Data: Numerical

Probability

Discrete Random Variables and Probability Distributions

Continuous Random Variables and Probability Distributions

Estimation: Single Population

Estimation: Additional Topics

Hypothesis Testing: Single Population

Hypothesis Testing: Additional Topics

Simple Regression

Multiple Regression

Additional Topics in Regression Analysis

Analysis of Categorical Data

Analysis of Variance

Time-Series Analysis and Forecasting

Additional Topics in Sampling

Filters

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: Given a population with mean μ=120 and variance σ² = 81,the central limit applies when the sample size is large-enough.A random sample of size n = 36 is obtained. -What is the probability that the sample mean is between 118 and 121?

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: Given a population with mean μ=120 and variance σ² = 81,the central limit applies when the sample size is large-enough.A random sample of size n = 36 is obtained. -What is the probability that the sample mean is at most 121.5?

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: A random sample of size n = 25 is obtained from a normally distributed population with population mean μ = 200 and variance σ²= 100. -What is the probability that the sample mean is greater than 203?

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: Given a population with mean μ=120 and variance σ² = 81,the central limit applies when the sample size is large-enough.A random sample of size n = 36 is obtained. -What is the probability that the sample mean is greater than 123?