Question 1

In a Gallup poll, 1011 adults were asked if they consume alcoholic beverages and 64% of
them said that they did. Construct a 90% confidence interval estimate of the proportion of all
adults who consume alcoholic beverages. Can we safely conclude that the majority of adults
consume alcoholic beverages?

Accepted Answer

61.5% < p < 66.5%. Because the...

Question 2

Use the given degree of confidence and sample data to construct a confidence interval for the population proportion  p .
 n=56, x=30 ; 95%  confidence

Accepted Answer

A)    0.405<p<0.667 
B)    0.425<p<0.647 
C)    0.426<p<0.646 
D)    0.404<p<0.668 E) A) and C)
F) B) and C)

Question 3

Identify the distribution that applies to the following situation: In constructing a confidence interval of ? , you have 50 sample values and they appear to be
From a population with a skewed distribution. The population standard deviation is not
Known. ______________

Accepted Answer

A)  Student t distribution
B)  Normal distribution
C)  Chi-square distribution
D)  None of the three distributions is appropriate.E) None of the above
F) A) and B)

Question 4

Express a confidence interval defined as  (0.432,0.52)   in the form of the point estimate __________ ±\pm±  the margin of error __________
Express both in three decimal places.

Accepted Answer

A)    0.476±0.0440.476 \pm 0.0440.476±0.044 
B)    0.476±0.0880.476 \pm 0.0880.476±0.088 
C)    0.432±0.0880.432 \pm 0.0880.432±0.088 
D)    0.432±0.0440.432 \pm 0.0440.432±0.044E) C) and D)
F) A) and B)

Question 5

In general, what does "degrees of freedom" refer to? Find the degrees of freedom for the
given information, assuming that you want to construct a confidence interval estimate of μ
 Six human skulls from around 4000 B.C. were measured, and the lengths have a mean of
94.2 mm and a standard deviation of 4.9 mm

Accepted Answer

The degrees of freedom is the ...

Question 6

Do one of the following, as appropriate: (a)  Find the critical value  zα/2z _ { \alpha / 2 }zα/2​ , (b)  find the critical value  tα/2t _ { \alpha / 2 }tα/2​ , (c)  state that neither the normal nor the  t  distribution applies.
 90%  confidence interval for  μ;n=9;σ=4.2\mu ; \quad n = 9 ; \sigma = 4.2μ;n=9;σ=4.2  population appears to be very skewed.

Accepted Answer

A)    za/2=2.896z _ { a / 2 } = 2.896za/2​=2.896 
B)    zα/2=2.365z _ { \alpha / 2 } = 2.365zα/2​=2.365 
C)    zα/2=2.306z _ { \alpha / 2 } = 2.306zα/2​=2.306 
D)   Neither the normal nor the  t  distribution applies. E) None of the above
F) A) and D)

Question 7

Why is $s ^ { 2 }$ the best point estimate of $\boldsymbol { \sigma } ^ { 2 }$ ?

Accepted Answer

51.0%; 46.8% < p < 55.1%.
No, ...

Question 8

A laboratory tested 82 chicken eggs and found that the mean amount of cholesterol was 228 milligrams with  σ=19,0\sigma = 19,0σ=19,0 milligrams. Construct a  95%  confidence interval for the true mean cholesterol content,   μ\muμ  of all such eggs.

Accepted Answer

A)    223mg<μ<232mg223 \mathrm { mg } < \mu < 232 \mathrm { mg }223mg<μ<232mg 
B)    224mg<μ<232mg224 \mathrm { mg } < \mu < 232 \mathrm { mg }224mg<μ<232mg 
C)    225mg<μ<233mg225 \mathrm { mg } < \mu < 233 \mathrm { mg }225mg<μ<233mg 
D)    223mg<μ<231mg223 \mathrm { mg } < \mu < 231 \mathrm { mg }223mg<μ<231mgE) All of the above
F) B) and C)

Question 9

Find the degree of confidence used in constructing the confidence interval  0.523<p<0.669  for the population proportion  p  using sample data with  n=109, x=65 .

Accepted Answer

A)    88% 
B)    90% 
C)    95% 
D)    99% E) All of the above
F) A) and B)

Question 10

Assume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level. Round the margin of error to four
Decimal places.
98% confidence; the sample size is 800, of which 40% are successes

Accepted Answer

A)  0.0355
B)  0.0339
C)  0.0404
D)  0.0446E) B) and C)
F) None of the above

Question 11

You want to be 95% confident that the sample variance is within 40% of the population variance. Find the appropriate minimum sample size.

Accepted Answer

A)  57
B)  224
C)  14
D)  11E) A) and C)
F) None of the above

Question 12

Fill in the blank: The critical value  zα/2z _ { \alpha / 2 }zα/2​  that corresponds to a _________% confidence level is 2.33.

Accepted Answer

A)  88
B)  90
C)  98
D)  99 E) A) and D)
F) A) and C)

Question 13

Find the critical value  χR2\chi _ { \mathrm { R } } ^ { 2 }χR2​  corresponding to a sample size of 19 and a confidence level of 99 percent.

Accepted Answer

A)    37.156 
B)    6.265 
C)    34.805 
D)    7.015  E) B) and D)
F) None of the above

Question 14

You want to estimate σ for the population of waiting times at McDonald's drive-up windows,
and you want to be 95% confident that the sample standard deviation is with 20% of $$\sigma$$ Find
the minimum sample size. Is this sample size practical?

Accepted Answer

The sample size of 48 is very ...

Question 15

Draw a diagram of the chi-square distribution. Discuss its shape and values.

Accepted Answer

The chi-square distribution is...

Question 16

Based on a simple random sample of students from her school, Sally obtained a point
estimate of the mean weight of students at her school. What additional information would
be provided by a confidence interval estimate of the mean weight?

Accepted Answer

A confidence interval provides a range o...

Question 17

Use the given degree of confidence and sample data to construct a confidence interval for the population proportion  p .
 n=130, x=69 ; 90 %  confidence

Accepted Answer

A)    0.458<p<0.604 
B)    0.461<p<0.601 
C)    0.459<p<0.603 
D)    0.463<p<0.599 E) A) and B)
F) A) and C)

Question 18

Find the critical value  zα/2z _ { \alpha / 2 }zα/2​  that corresponds to a  91%  confidence level.

Accepted Answer

A)    1.34 
B)    1.645 
C)    1.70 
D)    1.75  E) A) and B)
F) A) and C)

Question 19

Under what circumstances can you replace $\sigma$ with  s  in the formula $E = z _ { a / 2 } \cdot \frac { \sigma } { \sqrt { n } } ?$

Accepted Answer

Provided  n>30, s can be used ...

Question 20

Which critical value is appropriate for a  99 %  confidence level where  n=17 ;  σ\sigmaσ  is unknown and the population appears to be normally distributed?

Accepted Answer

A)    tα/2=2.898t _ { \alpha / 2 } = 2.898tα/2​=2.898 
B)    za/2=2.583z _ { a / 2 } = 2.583za/2​=2.583 
C)    tα/2=2.921t _ { \alpha / 2 } = 2.921tα/2​=2.921 
D)    zα/2=2.567z _ { \alpha / 2 } = 2.567zα/2​=2.567E) A) and B)
F) A) and C)

Exam 7: Estimating Parameters and Determining Sample Sizes

Draw a diagram of the chi-square distribution. Discuss its shape and values.

Correct Answer
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The chi-square distribution is...
View Answer

Based on a simple random sample of students from her school, Sally obtained a point estimate of the mean weight of students at her school. What additional information would be provided by a confidence interval estimate of the mean weight?

Correct Answer
verified
A confidence interval provides a range o...
View Answer

Find the critical value $\chi _ { \mathrm { R } } ^ { 2 }$ corresponding to a sample size of 19 and a confidence level of 99 percent.

Correct Answer
verified

Express a confidence interval defined as (0.432,0.52) in the form of the point estimate $\pm$ the margin of error Express both in three decimal places.

Correct Answer
verified

Correct Answer
verified
The degrees of freedom is the ...
View Answer

Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p . n=56, x=30 ; 95% confidence

Correct Answer
verified

Identify the distribution that applies to the following situation: In constructing a confidence interval of ? , you have 50 sample values and they appear to be From a population with a skewed distribution. The population standard deviation is not Known. ______________

Correct Answer
verified

Correct Answer
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61.5% < p < 66.5%. Because the...
View Answer

Find the degree of confidence used in constructing the confidence interval 0.523<p<0.669 for the population proportion p using sample data with n=109, x=65 .

Correct Answer
verified

Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p . n=130, x=69 ; 90 % confidence

Correct Answer
verified

You want to be 95% confident that the sample variance is within 40% of the population variance. Find the appropriate minimum sample size.

Correct Answer
verified

You want to estimate σ for the population of waiting times at McDonald's drive-up windows, and you want to be 95% confident that the sample standard deviation is with 20% of $\sigma$ Find the minimum sample size. Is this sample size practical?

Correct Answer
verified
The sample size of 48 is very ...
View Answer

Find the critical value $z _ { \alpha / 2 }$ that corresponds to a 91% confidence level.

Correct Answer
verified

Correct Answer
verified

A laboratory tested 82 chicken eggs and found that the mean amount of cholesterol was 228 milligrams with $\sigma = 19,0$ milligrams. Construct a 95% confidence interval for the true mean cholesterol content, $\mu$ of all such eggs.

Correct Answer
verified

Under what circumstances can you replace $\sigma$ with s in the formula $E = z _ { a / 2 } \cdot \frac { \sigma } { \sqrt { n } } ?$

Correct Answer
verified
Provided n>30, s can be used ...
View Answer

Fill in the blank: The critical value $z _ { \alpha / 2 }$ that corresponds to a _________% confidence level is 2.33.

Correct Answer
verified

Why is $s ^ { 2 }$ the best point estimate of $\boldsymbol { \sigma } ^ { 2 }$ ?

Correct Answer
verified
51.0%; 46.8% < p < 55.1%.
No, ...
View Answer

Assume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level. Round the margin of error to four Decimal places. 98% confidence; the sample size is 800, of which 40% are successes

Correct Answer
verified

Which critical value is appropriate for a 99 % confidence level where n=17 ; $\sigma$ is unknown and the population appears to be normally distributed?

Correct Answer
verified

Exam 7: Estimating Parameters and Determining Sample Sizes

Draw a diagram of the chi-square distribution. Discuss its shape and values.

Correct AnswerverifiedThe chi-square distribution is...View AnswerShow Answer

Based on a simple random sample of students from her school, Sally obtained a point estimate of the mean weight of students at her school. What additional information would be provided by a confidence interval estimate of the mean weight?

Correct AnswerverifiedA confidence interval provides a range o...View AnswerShow Answer

Find the critical value χR2\chi _ { \mathrm { R } } ^ { 2 }χR2​ corresponding to a sample size of 19 and a confidence level of 99 percent.

Correct AnswerverifiedShow Answer

Express a confidence interval defined as (0.432,0.52) in the form of the point estimate __________ ±\pm± the margin of error __________ Express both in three decimal places.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedThe degrees of freedom is the ...View AnswerShow Answer

Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p . n=56, x=30 ; 95% confidence

Correct AnswerverifiedShow Answer

Identify the distribution that applies to the following situation: In constructing a confidence interval of ? , you have 50 sample values and they appear to be From a population with a skewed distribution. The population standard deviation is not Known. ______________

Correct AnswerverifiedShow Answer

Correct Answerverified61.5% < p < 66.5%. Because the...View AnswerShow Answer

Find the degree of confidence used in constructing the confidence interval 0.523<p<0.669 for the population proportion p using sample data with n=109, x=65 .

Correct AnswerverifiedShow Answer

Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p . n=130, x=69 ; 90 % confidence

Correct AnswerverifiedShow Answer

You want to be 95% confident that the sample variance is within 40% of the population variance. Find the appropriate minimum sample size.

Correct AnswerverifiedShow Answer

You want to estimate σ for the population of waiting times at McDonald's drive-up windows, and you want to be 95% confident that the sample standard deviation is with 20% of σ\sigmaσ Find the minimum sample size. Is this sample size practical?

Correct AnswerverifiedThe sample size of 48 is very ...View AnswerShow Answer

Find the critical value zα/2z _ { \alpha / 2 }zα/2​ that corresponds to a 91% confidence level.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A laboratory tested 82 chicken eggs and found that the mean amount of cholesterol was 228 milligrams with σ=19,0\sigma = 19,0σ=19,0 milligrams. Construct a 95% confidence interval for the true mean cholesterol content, μ\muμ of all such eggs.

Correct AnswerverifiedShow Answer

Under what circumstances can you replace σ\sigmaσ with s in the formula E=za/2⋅σn?E = z _ { a / 2 } \cdot \frac { \sigma } { \sqrt { n } } ?E=za/2​⋅n​σ​?

Correct AnswerverifiedProvided n>30, s can be used ...View AnswerShow Answer

Fill in the blank: The critical value zα/2z _ { \alpha / 2 }zα/2​ that corresponds to a _________% confidence level is 2.33.

Correct AnswerverifiedShow Answer

Why is s2s ^ { 2 }s2 the best point estimate of σ2\boldsymbol { \sigma } ^ { 2 }σ2 ?

Correct Answerverified51.0%; 46.8% < p < 55.1%.No, ...View AnswerShow Answer

Assume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level. Round the margin of error to four Decimal places. 98% confidence; the sample size is 800, of which 40% are successes

Correct AnswerverifiedShow Answer

Which critical value is appropriate for a 99 % confidence level where n=17 ; σ\sigmaσ is unknown and the population appears to be normally distributed?

Correct AnswerverifiedShow Answer

Correct Answer
verified
The chi-square distribution is...
View Answer

Correct Answer
verified
A confidence interval provides a range o...
View Answer

Find the critical value $\chi _ { \mathrm { R } } ^ { 2 }$ corresponding to a sample size of 19 and a confidence level of 99 percent.

Correct Answer
verified

Express a confidence interval defined as (0.432,0.52) in the form of the point estimate $\pm$ the margin of error Express both in three decimal places.

Correct Answer
verified

Correct Answer
verified
The degrees of freedom is the ...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
61.5% < p < 66.5%. Because the...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

You want to estimate σ for the population of waiting times at McDonald's drive-up windows, and you want to be 95% confident that the sample standard deviation is with 20% of $\sigma$ Find the minimum sample size. Is this sample size practical?

Correct Answer
verified
The sample size of 48 is very ...
View Answer

Find the critical value $z _ { \alpha / 2 }$ that corresponds to a 91% confidence level.

Correct Answer
verified

Correct Answer
verified

A laboratory tested 82 chicken eggs and found that the mean amount of cholesterol was 228 milligrams with $\sigma = 19,0$ milligrams. Construct a 95% confidence interval for the true mean cholesterol content, $\mu$ of all such eggs.

Correct Answer
verified

Under what circumstances can you replace $\sigma$ with s in the formula $E = z _ { a / 2 } \cdot \frac { \sigma } { \sqrt { n } } ?$

Correct Answer
verified
Provided n>30, s can be used ...
View Answer

Fill in the blank: The critical value $z _ { \alpha / 2 }$ that corresponds to a _________% confidence level is 2.33.

Correct Answer
verified

Why is $s ^ { 2 }$ the best point estimate of $\boldsymbol { \sigma } ^ { 2 }$ ?

Correct Answer
verified
51.0%; 46.8% < p < 55.1%.
No, ...
View Answer

Correct Answer
verified

Which critical value is appropriate for a 99 % confidence level where n=17 ; $\sigma$ is unknown and the population appears to be normally distributed?

Correct Answer
verified