Question 1

The density function of the standard normal distribution has a wider dispersion than the Student's t distribution.

Accepted Answer

A) True 
 B)False

Question 2

All other things being equal,the larger the sample size,the narrower the interval estimates that reflect the uncertainty about a parameter's true value.

Accepted Answer

A) True 
 B)False

Question 3

The amount of material used in making a custom sail for a sailboat is normally distributed.For a random sample of 15 sails,you find that the mean amount of material is 912 square feet,with a standard deviation of 64 square feet.Develop a 99% confidence interval for the population mean amount of material used in a custom sail.

Accepted Answer

@#IMG-DLM& ± t_n_-1,_α/2 s/ @#IMG-DLM& = 912 ± (2

Question 4

A student records the time (in minutes)it takes to commute to school for seven days.Those results are: 21,15,13,16,10,13,and 18.Assuming the population is normally distributed,develop a 95% confidence interval for the population mean.

Accepted Answer

@#IMG-DLM& = 15.143,s = 3.625,t_n_-1,α/2 = t_6,0.025 = 2

Question 5

If a sample of size 30 is selected,the value of A for the probability P(t ≥A)= 0.01 is:

Accepted Answer

A) 2.247 
B) 2.045 
C) 2.462 
D) 2.750 
A) 2.247 
B) 2.045 
C) 2.462 
D) 2.750

Question 6

If Var (   1)= σ2 and Var (   2)= 2σ2,then the relative efficiency of   
1 with respect to   
2 is equal to 0.5.

Accepted Answer

A) True 
 B)False

Question 7

The lower limit of the 90% confidence interval for the population proportion P,given that n = 400;and   
= 0.10 is 0.1247.

Accepted Answer

A) True 
 B)False

Question 8

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A clinic offers a weight-reduction program.A review of its records revealed the following weight losses,in pounds,for a random sample of 10 of its clients at the conclusion of the program: 20,15,21,28,22,19,9,14,18,and 23.
-To calculate a required sample size to estimate a population proportion,given a desired confidence interval and margin of error,the sample proportion is required but often unknown before the sample is collected.How is this predicament resolved?

Accepted Answer

Without any additional information,the m

Question 9

For a population that is normally distributed with a very large population size compared to the sample size,the variance of the sample mean   is given by:

Accepted Answer

A) σ /   
B) σ2 /   
C) σ / n 
D) σ2 / n 
A) σ /   
B) σ2 /   
C) σ / n 
D) σ2 / n

Question 10

The dollar value of orders placed through a particular store catalog is found to be normally distributed with a standard deviation of $21.58.A sample of 30 orders averaged $81.25.What is the 90% confidence interval around this sample mean?

Accepted Answer

A) $81.25 ± $21.58 
B) $81.25 ± $10.79 
C) $81.25 ± $12.15 
D) $81.25 ± $6.48 
A) $81.25 ± $21.58 
B) $81.25 ± $10.79 
C) $81.25 ± $12.15 
D) $81.25 ± $6.48

Question 11

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
The data shown below specify how much a sample of 20 executives paid in federal income taxes,as a percentage of gross income,are reproduced below.
   
Assume that the standard deviation for the underlying population is equal to 4.0.
-Give a careful verbal interpretation of the 99% confidence interval for the population mean.

Accepted Answer

We would expect that 99% of all confiden

The density function of the standard normal distribution has a wider dispersion than the Student's t distribution.

All other things being equal,the larger the sample size,the narrower the interval estimates that reflect the uncertainty about a parameter's true value.

A student records the time (in minutes)it takes to commute to school for seven days.Those results are: 21,15,13,16,10,13,and 18.Assuming the population is normally distributed,develop a 95% confidence interval for the population mean.

If a sample of size 30 is selected,the value of A for the probability P(t ≥A)= 0.01 is:

If Var ( ₁)= σ² and Var ( ₂)= 2σ²,then the relative efficiency of ₁ with respect to ₂ is equal to 0.5.

The lower limit of the 90% confidence interval for the population proportion P,given that n = 400;and = 0.10 is 0.1247.

For a population that is normally distributed with a very large population size compared to the sample size,the variance of the sample mean is given by:

The dollar value of orders placed through a particular store catalog is found to be normally distributed with a standard deviation of $21.58.A sample of 30 orders averaged $81.25.What is the 90% confidence interval around this sample mean?

Describing Data: Graphical

Describing Data: Numerical

Probability

Discrete Random Variables and Probability Distributions

Continuous Random Variables and Probability Distributions

Sampling and Sampling Distributions

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 7: Estimation: Single Population

The density function of the standard normal distribution has a wider dispersion than the Student's t distribution.

All other things being equal,the larger the sample size,the narrower the interval estimates that reflect the uncertainty about a parameter's true value.

A student records the time (in minutes)it takes to commute to school for seven days.Those results are: 21,15,13,16,10,13,and 18.Assuming the population is normally distributed,develop a 95% confidence interval for the population mean.

If a sample of size 30 is selected,the value of A for the probability P(t ≥A)= 0.01 is:

If Var ( 1)= σ2 and Var ( 2)= 2σ2,then the relative efficiency of 1 with respect to 2 is equal to 0.5.

The lower limit of the 90% confidence interval for the population proportion P,given that n = 400;and = 0.10 is 0.1247.

For a population that is normally distributed with a very large population size compared to the sample size,the variance of the sample mean is given by:

The dollar value of orders placed through a particular store catalog is found to be normally distributed with a standard deviation of $21.58.A sample of 30 orders averaged $81.25.What is the 90% confidence interval around this sample mean?

Describing Data: Graphical

Describing Data: Numerical

Probability

Discrete Random Variables and Probability Distributions

Continuous Random Variables and Probability Distributions

Sampling and Sampling Distributions

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

If Var ( ₁)= σ² and Var ( ₂)= 2σ²,then the relative efficiency of ₁ with respect to ₂ is equal to 0.5.