Question 1

Write the word or phrase that best completes each statement or answers the question.
-The grade point averages for 10 randomly selected students in a statistics class with 125 students are listed below. What can you say about the mean score $\mu$ of all 125 students?
$$\begin{array} { l l l l l l l l l l } 
3.0 & 2.7 & 3.2 & 2.8 & 2.2 & 3.8 & 3.7 & 2.1 & 3.6 & 3.4
\end{array}$$

Accepted Answer

The answer of Write the word or phrase that best...

Question 2

Provide an appropriate response.
-How much money does the average professional hockey fan spend on food at a single hockey game? That question was posed to 10 randomly selected hockey fans. The sampled results show that sample mean and standard deviation were  $19.00\$ 19.00$19.00  and  $3.35\$ 3.35$3.35 , respectively. Use this information to create a  98%98 \%98%  confidence interval for the mean.

Accepted Answer

A)    19±2.821(3.35/10) 19 \pm 2.821 ( 3.35 / \sqrt { 10 } ) 19±2.821(3.35/10c-2.7,0,-7.17,-2.7,-13.5,-8c-5.8,-5.3,-9.5,-10,-9.5,-14c0,-2,0.3,-3.3,1,-4c1.3,-2.7,23.83,-20.7,67.5,-54c44.2,-33.3,65.8,-50.3,66.5,-51c1.3,-1.3,3,-2,5,-2c4.7,0,8.7,3.3,12,10s173,378,173,378c0.7,0,35.3,-71,104,-213c68.7,-142,137.5,-285,206.5,-429c69,-144,104.5,-217.7,106.5,-221l0 -0c5.3,-9.3,12,-14,20,-14H400000v40H845.2724s-225.272,467,-225.272,467s-235,486,-235,486c-2.7,4.7,-9,7,-19,7c-6,0,-10,-1,-12,-3s-194,-422,-194,-422s-65,47,-65,47zM834 80h400000v40h-400000z'/>​)  
B)    19±2.764(3.35/10) 19 \pm 2.764 ( 3.35 / \sqrt { 10 } ) 19±2.764(3.35/10c-2.7,0,-7.17,-2.7,-13.5,-8c-5.8,-5.3,-9.5,-10,-9.5,-14c0,-2,0.3,-3.3,1,-4c1.3,-2.7,23.83,-20.7,67.5,-54c44.2,-33.3,65.8,-50.3,66.5,-51c1.3,-1.3,3,-2,5,-2c4.7,0,8.7,3.3,12,10s173,378,173,378c0.7,0,35.3,-71,104,-213c68.7,-142,137.5,-285,206.5,-429c69,-144,104.5,-217.7,106.5,-221l0 -0c5.3,-9.3,12,-14,20,-14H400000v40H845.2724s-225.272,467,-225.272,467s-235,486,-235,486c-2.7,4.7,-9,7,-19,7c-6,0,-10,-1,-12,-3s-194,-422,-194,-422s-65,47,-65,47zM834 80h400000v40h-400000z'/>​)  
C)    19±2.718(3.35/10) 19 \pm 2.718 ( 3.35 / \sqrt { 10 } ) 19±2.718(3.35/10c-2.7,0,-7.17,-2.7,-13.5,-8c-5.8,-5.3,-9.5,-10,-9.5,-14c0,-2,0.3,-3.3,1,-4c1.3,-2.7,23.83,-20.7,67.5,-54c44.2,-33.3,65.8,-50.3,66.5,-51c1.3,-1.3,3,-2,5,-2c4.7,0,8.7,3.3,12,10s173,378,173,378c0.7,0,35.3,-71,104,-213c68.7,-142,137.5,-285,206.5,-429c69,-144,104.5,-217.7,106.5,-221l0 -0c5.3,-9.3,12,-14,20,-14H400000v40H845.2724s-225.272,467,-225.272,467s-235,486,-235,486c-2.7,4.7,-9,7,-19,7c-6,0,-10,-1,-12,-3s-194,-422,-194,-422s-65,47,-65,47zM834 80h400000v40h-400000z'/>​)  
D)    19±2.262(3.35/10) 19 \pm 2.262 ( 3.35 / \sqrt { 10 } ) 19±2.262(3.35/10c-2.7,0,-7.17,-2.7,-13.5,-8c-5.8,-5.3,-9.5,-10,-9.5,-14c0,-2,0.3,-3.3,1,-4c1.3,-2.7,23.83,-20.7,67.5,-54c44.2,-33.3,65.8,-50.3,66.5,-51c1.3,-1.3,3,-2,5,-2c4.7,0,8.7,3.3,12,10s173,378,173,378c0.7,0,35.3,-71,104,-213c68.7,-142,137.5,-285,206.5,-429c69,-144,104.5,-217.7,106.5,-221l0 -0c5.3,-9.3,12,-14,20,-14H400000v40H845.2724s-225.272,467,-225.272,467s-235,486,-235,486c-2.7,4.7,-9,7,-19,7c-6,0,-10,-1,-12,-3s-194,-422,-194,-422s-65,47,-65,47zM834 80h400000v40h-400000z'/>​)

Question 3

Choose the one alternative that best completes the statement or answers the question.
-A random sample of 56 lithium batteries has a mean life of 645 hours with a population standard deviation of 31 hours. Compute the  95%95 \%95%  confidence interval for  μ\muμ .

Accepted Answer

A)    (636.9,653.1) ( 636.9,653.1 ) (636.9,653.1)  
B)    (539.6,551.2) ( 539.6,551.2 ) (539.6,551.2)  
C)    (112.0,118.9) ( 112.0,118.9 ) (112.0,118.9)  
D)    (712.0,768.0) ( 712.0,768.0 ) (712.0,768.0)

Question 4

State the Properties of Student s t-Distribution
-Suppose a  99%99 \%99%  confidence interval for  μ\muμ  turns out to be  (1000,2100) ( 1000,2100 ) (1000,2100)  . If this interval was based on a sample of size  n=26n = 26n=26 , explain what assumptions are necessary for this interval to be valid.

Accepted Answer

A)   The population must have an approximately normal distribution.
B)   The sampling distribution of the sample mean must have a normal distribution.
C)   The population of salaries must have an approximate  ttt  distribution.
D)   The sampling distribution must be biased with 25 degrees of freedom.

Question 5

Provide an appropriate response.
-What is the best point estimate for  ppp  in order to construct a confidence interval for  ppp  ?

Accepted Answer

A)    p^\hat { p }p^​ 
B)    μp\mu _ { \mathrm { p } }μp​ 
C)    p‾\overline { \mathrm { p } }p​ 
D)    ppp

Question 6

Provide an appropriate response.
-In a college student poll, it is of interest to estimate the proportion  ppp  of students in favor of changing from a quarter-system to a semester-system. How many students should be polled so that we can estimate p to within  0.090.090.09  using a  99%99 \%99%  confidence interval?

Accepted Answer

A)   205
B)   182
C)   261
D)   114

Question 7

Choose the one alternative that best completes the statement or answers the question.
-The margin of error of a confidence interval is

Accepted Answer

A)    ±zα/2σn\pm z _ { \alpha / 2 } \frac { \sigma } { \sqrt { n } }±zα/2​nc-2.7,0,-7.17,-2.7,-13.5,-8c-5.8,-5.3,-9.5,-10,-9.5,-14c0,-2,0.3,-3.3,1,-4c1.3,-2.7,23.83,-20.7,67.5,-54c44.2,-33.3,65.8,-50.3,66.5,-51c1.3,-1.3,3,-2,5,-2c4.7,0,8.7,3.3,12,10s173,378,173,378c0.7,0,35.3,-71,104,-213c68.7,-142,137.5,-285,206.5,-429c69,-144,104.5,-217.7,106.5,-221l0 -0c5.3,-9.3,12,-14,20,-14H400000v40H845.2724s-225.272,467,-225.272,467s-235,486,-235,486c-2.7,4.7,-9,7,-19,7c-6,0,-10,-1,-12,-3s-194,-422,-194,-422s-65,47,-65,47zM834 80h400000v40h-400000z'/>​σ​ 
B)    zα/2\mathrm { z } _ { \alpha / 2 }zα/2​ 
C)    xˉ\bar { x }xˉ 
D)    σn\frac { \sigma } { \sqrt { n } }nc-2.7,0,-7.17,-2.7,-13.5,-8c-5.8,-5.3,-9.5,-10,-9.5,-14c0,-2,0.3,-3.3,1,-4c1.3,-2.7,23.83,-20.7,67.5,-54c44.2,-33.3,65.8,-50.3,66.5,-51c1.3,-1.3,3,-2,5,-2c4.7,0,8.7,3.3,12,10s173,378,173,378c0.7,0,35.3,-71,104,-213c68.7,-142,137.5,-285,206.5,-429c69,-144,104.5,-217.7,106.5,-221l0 -0c5.3,-9.3,12,-14,20,-14H400000v40H845.2724s-225.272,467,-225.272,467s-235,486,-235,486c-2.7,4.7,-9,7,-19,7c-6,0,-10,-1,-12,-3s-194,-422,-194,-422s-65,47,-65,47zM834 80h400000v40h-400000z'/>​σ​

Question 8

Choose the one alternative that best completes the statement or answers the question.
-Determine the point estimate of the population mean for the confidence interval with a lower bound of 19 and an upper bound of 25 .

Accepted Answer

A)   22
B)   19
C)   25
D)   23

Question 9

Provide an appropriate response.
-Construct a  90%90 \%90%  confidence interval for the population mean,  μ\muμ . Assume the population has a normal distribution. A sample of 15 randomly selected math majors has a grade point average of  2.862.862.86  with a standard deviation of  0.780.780.78 .

Accepted Answer

A)    (2.51,3.21) ( 2.51,3.21 ) (2.51,3.21)  
B)    (2.41,3.42) ( 2.41,3.42 ) (2.41,3.42)  
C)    (2.37,3.56) ( 2.37,3.56 ) (2.37,3.56)  
D)    (2.28,3.66) ( 2.28,3.66 ) (2.28,3.66)

Question 10

Explain the Role of Margin of Error in Constructing a Confidence Interval
-Suppose a 95% confidence interval for turns out to be (130, 300) . To make more useful inferences from the data, it is desired to reduce the width of the confidence interval. Which of the following will result in a reduced interval width

Accepted Answer

A)   All of these.
B)   Increase the sample size.
C)   Decrease the confidence level.
D)   Increase the sample size and decrease the confidence level.

Question 11

Provide an appropriate response.
-A survey of 700 non-fatal accidents showed that 272 involved uninsured drivers. Construct a $99 \%$ confidence interval for the proportion of fatal accidents that involved uninsured drivers.

Accepted Answer

The answer of Provide an appropriate response.
-A survey of 700...

Question 12

Provide an appropriate response.
-The mean replacement time for a random sample of  12 cd12 \mathrm {~cd}12 cd  players is  8.68.68.6  years with a standard deviation of  5.15.15.1  years. Construct the  98%98 \%98%  confidence interval for the population variance,  σ2\sigma ^ { 2 }σ2 . Assume the data are normally distributed

Accepted Answer

A)    (11.6,93.7) ( 11.6,93.7 ) (11.6,93.7)  
B)    (3.4,9.7) ( 3.4,9.7 ) (3.4,9.7)  
C)    (2.3,18.4) ( 2.3,18.4 ) (2.3,18.4)  
D)    (10.9,80.1) ( 10.9,80.1 ) (10.9,80.1)

Question 13

Provide an appropriate response.
-The best point estimate for the standard deviation of a population is

Accepted Answer

A)   The standard deviation of the sample.
B)   The variance of the population.
C)   The variance of the sample.
D)    (n−1) s2σ2\frac { ( n - 1 )  s ^ { 2 } } { \sigma ^ { 2 } }σ2(n−1) s2​ .

Question 14

Provide an appropriate response.
-Construct a  95%95 \%95%  confidence interval for the population mean,  μ\muμ . Assume the population has a normal distribution. A sample of 20 part-time workers had mean annual earnings of  $3120\$ 3120$3120  with a standard deviation of  $677\$ 677$677 .

Accepted Answer

A)    ($2803,$3437) ( \$ 2803 , \$ 3437 ) ($2803,$3437)  
B)    ($1324,$1567) ( \$ 1324 , \$ 1567 ) ($1324,$1567)  
C)    ($2135,$2567) ( \$ 2135 , \$ 2567 ) ($2135,$2567)  
D)    ($2657,$2891) ( \$ 2657 , \$ 2891 ) ($2657,$2891)

Question 15

Provide an appropriate response.
-In a random sample of 26 laptop computers, the mean repair cost was $\$ 157$ with a standard deviation of $\$ 38$. Assume the population has a normal distribution.
a) Construct a $95 \%$ confidence interval for the population mean, $\mu$.
b) Suppose you did some research on repair costs for laptop computers and found that the standard deviation is $\sigma = 38$. Use the normal distribution to construct a $95 \%$ confidence interval for the population mean, $\mu$. Compare the results.

Accepted Answer

a) <img  loading="lazy" src="/assets/images/blured-textbook.svg" class="d-inline m-1" alt="blured image" width="139" height="30"><br>b) <img  loading="lazy" src="/assets/images/blured-textbook.svg" class="d-inline m-1" alt="blured image" width="139" height="30">; T...

Question 16

Determine t-values
-Let to be a specific value of  ttt . Find  t0t _ { 0 }t0​  such that the following statement is true:  P(t≥t0) =0.1P \left( t \geq t _ { 0 } \right)  = 0.1P(t≥t0​) =0.1  where  df=20d f = 20df=20

Accepted Answer

A)    1.3251.3251.325 
B)    −1.325- 1.325−1.325 
C)    1.3281.3281.328 
D)    −1.328- 1.328−1.328

Question 17

Choose the one alternative that best completes the statement or answers the question.
-A point estimate is the value of a_____ that estimates the value of a_____

Accepted Answer

A)   statistic; parameter
B)   parameter; statistic
C)   random variable; statistic
D)   random variable; parameter

Question 18

Provide an appropriate response.
-A state highway patrol official wishes to estimate the number of legally intoxicated drivers on a certain road.
a) How large a sample is needed in order to be $99 \%$ confident that the sample proportion will not differ from the true proportion by more than $2 \%$ ?
b) Repeat part (a) assuming previous studies found that $80 \%$ of the drivers on this road are legally intoxicated.

Accepted Answer

The answer of Provide an appropriate response.
-A state highway patrol...

Question 19

Provide an appropriate response.
-A senator wishes to estimate the proportion of United States voters who favor abolishing the Electoral College. How large a sample is needed in order to be  98%98 \%98%  confident that the sample proportion will not differ from the true proportion by more than  5%5 \%5%  ?

Accepted Answer

A)   543
B)   385
C)   12
D)   1086

Question 20

Determine the Sample Size Necessary for Estimating the Population Mean within a Specified Margin of Error
- E=4,σ=35, (1−α) =0.90\mathrm { E } = 4 , \sigma = 35 	ext {, } ( 1 - \alpha )  = 0.90E=4,σ=35, (1−α) =0.90

Accepted Answer

A)   208
B)   207
C)   4
D)   295

Exam 9: Estimating the Value of a Parameter Using Confidence Intervals

Correct Answer
verified

State the Properties of Student s t-Distribution -Suppose a $99 \%$ confidence interval for $\mu$ turns out to be $( 1000,2100 )$ . If this interval was based on a sample of size $n = 26$ , explain what assumptions are necessary for this interval to be valid.

Correct Answer
verified

Choose the one alternative that best completes the statement or answers the question. -A point estimate is the value of a_ that estimates the value of a_

Correct Answer
verified

Provide an appropriate response. -Construct a $90 \%$ confidence interval for the population mean, $\mu$ . Assume the population has a normal distribution. A sample of 15 randomly selected math majors has a grade point average of $2.86$ with a standard deviation of $0.78$ .

Correct Answer
verified

Provide an appropriate response. -Construct a $95 \%$ confidence interval for the population mean, $\mu$ . Assume the population has a normal distribution. A sample of 20 part-time workers had mean annual earnings of $\$ 3120$ with a standard deviation of $\$ 677$ .

Correct Answer
verified

Provide an appropriate response. -The mean replacement time for a random sample of $12 \mathrm {~cd}$ players is $8.6$ years with a standard deviation of $5.1$ years. Construct the $98 \%$ confidence interval for the population variance, $\sigma ^ { 2 }$ . Assume the data are normally distributed

Correct Answer
verified

Correct Answer
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a)
b) ; T...
View Answer

Correct Answer
verified

Provide an appropriate response. -What is the best point estimate for $p$ in order to construct a confidence interval for $p$ ?

Correct Answer
verified

Choose the one alternative that best completes the statement or answers the question. -The margin of error of a confidence interval is

Correct Answer
verified

Provide an appropriate response. -A senator wishes to estimate the proportion of United States voters who favor abolishing the Electoral College. How large a sample is needed in order to be $98 \%$ confident that the sample proportion will not differ from the true proportion by more than $5 \%$ ?

Correct Answer
verified

Correct Answer
verified

Choose the one alternative that best completes the statement or answers the question. -A random sample of 56 lithium batteries has a mean life of 645 hours with a population standard deviation of 31 hours. Compute the $95 \%$ confidence interval for $\mu$ .

Correct Answer
verified

Correct Answer
verified

Provide an appropriate response. -A survey of 700 non-fatal accidents showed that 272 involved uninsured drivers. Construct a $99 \%$ confidence interval for the proportion of fatal accidents that involved uninsured drivers.

Correct Answer
verified

Correct Answer
verified

Provide an appropriate response. -The best point estimate for the standard deviation of a population is

Correct Answer
verified

Determine the Sample Size Necessary for Estimating the Population Mean within a Specified Margin of Error - $\mathrm { E } = 4 , \sigma = 35 \text {, } ( 1 - \alpha ) = 0.90$

Correct Answer
verified

Choose the one alternative that best completes the statement or answers the question. -Determine the point estimate of the population mean for the confidence interval with a lower bound of 19 and an upper bound of 25 .

Correct Answer
verified

Determine t-values -Let to be a specific value of $t$ . Find $t _ { 0 }$ such that the following statement is true: $P \left( t \geq t _ { 0 } \right) = 0.1$ where $d f = 20$

Correct Answer
verified

Exam 9: Estimating the Value of a Parameter Using Confidence Intervals

Correct AnswerverifiedShow Answer

State the Properties of Student s t-Distribution -Suppose a 99%99 \%99% confidence interval for μ\muμ turns out to be (1000,2100) ( 1000,2100 ) (1000,2100) . If this interval was based on a sample of size n=26n = 26n=26 , explain what assumptions are necessary for this interval to be valid.

Correct AnswerverifiedShow Answer

Choose the one alternative that best completes the statement or answers the question. -A point estimate is the value of a_____ that estimates the value of a_____

Correct AnswerverifiedShow Answer

Provide an appropriate response. -Construct a 90%90 \%90% confidence interval for the population mean, μ\muμ . Assume the population has a normal distribution. A sample of 15 randomly selected math majors has a grade point average of 2.862.862.86 with a standard deviation of 0.780.780.78 .

Correct AnswerverifiedShow Answer

Provide an appropriate response. -Construct a 95%95 \%95% confidence interval for the population mean, μ\muμ . Assume the population has a normal distribution. A sample of 20 part-time workers had mean annual earnings of $3120\$ 3120$3120 with a standard deviation of $677\$ 677$677 .

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct Answerverifieda) b) ; T...View AnswerShow Answer

Correct AnswerverifiedShow Answer

Provide an appropriate response. -What is the best point estimate for ppp in order to construct a confidence interval for ppp ?

Correct AnswerverifiedShow Answer

Choose the one alternative that best completes the statement or answers the question. -The margin of error of a confidence interval is

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Choose the one alternative that best completes the statement or answers the question. -A random sample of 56 lithium batteries has a mean life of 645 hours with a population standard deviation of 31 hours. Compute the 95%95 \%95% confidence interval for μ\muμ .

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Provide an appropriate response. -A survey of 700 non-fatal accidents showed that 272 involved uninsured drivers. Construct a 99%99 \%99% confidence interval for the proportion of fatal accidents that involved uninsured drivers.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Provide an appropriate response. -The best point estimate for the standard deviation of a population is

Correct AnswerverifiedShow Answer

Determine the Sample Size Necessary for Estimating the Population Mean within a Specified Margin of Error - E=4,σ=35, (1−α) =0.90\mathrm { E } = 4 , \sigma = 35 \text {, } ( 1 - \alpha ) = 0.90E=4,σ=35, (1−α) =0.90

Correct AnswerverifiedShow Answer

Choose the one alternative that best completes the statement or answers the question. -Determine the point estimate of the population mean for the confidence interval with a lower bound of 19 and an upper bound of 25 .

Correct AnswerverifiedShow Answer

Determine t-values -Let to be a specific value of ttt . Find t0t _ { 0 }t0​ such that the following statement is true: P(t≥t0) =0.1P \left( t \geq t _ { 0 } \right) = 0.1P(t≥t0​) =0.1 where df=20d f = 20df=20

Correct AnswerverifiedShow Answer

Correct Answer
verified

State the Properties of Student s t-Distribution -Suppose a $99 \%$ confidence interval for $\mu$ turns out to be $( 1000,2100 )$ . If this interval was based on a sample of size $n = 26$ , explain what assumptions are necessary for this interval to be valid.

Correct Answer
verified

Choose the one alternative that best completes the statement or answers the question. -A point estimate is the value of a_ that estimates the value of a_

Correct Answer
verified

Provide an appropriate response. -Construct a $90 \%$ confidence interval for the population mean, $\mu$ . Assume the population has a normal distribution. A sample of 15 randomly selected math majors has a grade point average of $2.86$ with a standard deviation of $0.78$ .

Correct Answer
verified

Provide an appropriate response. -Construct a $95 \%$ confidence interval for the population mean, $\mu$ . Assume the population has a normal distribution. A sample of 20 part-time workers had mean annual earnings of $\$ 3120$ with a standard deviation of $\$ 677$ .

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
a)
b) ; T...
View Answer

Correct Answer
verified

Provide an appropriate response. -What is the best point estimate for $p$ in order to construct a confidence interval for $p$ ?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Choose the one alternative that best completes the statement or answers the question. -A random sample of 56 lithium batteries has a mean life of 645 hours with a population standard deviation of 31 hours. Compute the $95 \%$ confidence interval for $\mu$ .

Correct Answer
verified

Correct Answer
verified

Provide an appropriate response. -A survey of 700 non-fatal accidents showed that 272 involved uninsured drivers. Construct a $99 \%$ confidence interval for the proportion of fatal accidents that involved uninsured drivers.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Determine the Sample Size Necessary for Estimating the Population Mean within a Specified Margin of Error - $\mathrm { E } = 4 , \sigma = 35 \text {, } ( 1 - \alpha ) = 0.90$

Correct Answer
verified

Correct Answer
verified

Determine t-values -Let to be a specific value of $t$ . Find $t _ { 0 }$ such that the following statement is true: $P \left( t \geq t _ { 0 } \right) = 0.1$ where $d f = 20$

Correct Answer
verified