Question 1

The pooled-variances t-test requires the assumption that the two population ___________________________________ are equal,and that the populations are at least ___________________________________ distributed.

Accepted Answer

The answer of The pooled-variances t-test requires the assumption that...

Question 2

Price earnings
A comparison of the price-earnings (P/E)ratio for the top and bottom 100 companies in valuation is being prepared.A financial advisor randomly sampled each group to determine whether there is any difference in P/E ratios of the two groups of companies.Let 1 = a top 100 company and 2 = a bottom 100 company.Assume equal population variances and that the populations are normally distributed.The advisor is to use a 0.01 significance level.The data were randomly selected and are summarized below: $$\begin{array} { | c | c | } 
\hline \text { Top 100 company } & \text { Bottom 100 company } \
\hline n _ { 1 } = 6 & n _ { 2 } = 6 \
\bar { x } _ { 1 } = 18.83 & \bar { x } _ { 2 } = 10.67 \
s _ { 1 } ^ { 2 } = 128.17 & s _ { 2 } ^ { 2 } = 8.67 \
\hline
\end{array}$$
-What is the conclusion?

Accepted Answer

The answer of Price earnings
A comparison of the price-earnings (P/E)ratio...

Question 3

Price earnings
A comparison of the price-earnings (P/E)ratio for the top and bottom 100 companies in valuation is being prepared.A financial advisor randomly sampled each group to determine whether there is any difference in P/E ratios of the two groups of companies.Let 1 = a top 100 company and 2 = a bottom 100 company.Assume equal population variances and that the populations are normally distributed.The advisor is to use a 0.01 significance level.The data were randomly selected and are summarized below: $$\begin{array} { | c | c | } 
\hline \text { Top 100 company } & \text { Bottom 100 company } \
\hline n _ { 1 } = 6 & n _ { 2 } = 6 \
\bar { x } _ { 1 } = 18.83 & \bar { x } _ { 2 } = 10.67 \
s _ { 1 } ^ { 2 } = 128.17 & s _ { 2 } ^ { 2 } = 8.67 \
\hline
\end{array}$$
-What is the decision rule?

Accepted Answer

The answer of Price earnings
A comparison of the price-earnings (P/E)ratio...

Question 4

When comparing the means of two independent samples,the ____________________ is applicable whenever the population standard deviations are unknown.

Accepted Answer

The answer of When comparing the means of two independent...

Question 5

Battery A new brand of battery for use in calculators and cameras is said to last significantly longer than another brand.A camera manufacturer is to test this brand (Y)with brand (X)to see if brand Y has a longer life.If brand Y does last longer,the camera manufacturer will equip their new cameras with them.If not,they will equip them with brand X that is less costly.Twenty cameras are equipped as follows: ten with brand Y batteries and ten with brand X batteries and the life of the batteries measured.Is brand Y superior (does it last longer)to brand X? To answer this question,the camera manufacturer uses a 0.01 significance level and knows that the populations are normally distributed with equal variances.Sample data are: $$\begin{array} { | c | c | } \hline \text { Brand } \boldsymbol { X } & \text { Brand } \boldsymbol { Y } \ \hline n _ { 1 } = 10 & n _ { 2 } = 10 \ \bar { x } _ { 1 } = 500 \text { hours } & \bar { x } _ { 2 } = 650 \text { hours } \ s _ { 1 } ^ { 2 } = 400 & s _ { 2 } ^ { 2 } = 484 \ \hline \end{array}$$ -State the null and alternative hypotheses. H₀: ____________________ H₁: ____________________

Accepted Answer

The answer of Battery
A new brand of battery for use...

Question 6

The ____________________ approximation is an alternative to the unequal-variances t-test whenever both n₁ and n₂ are ≥ 30.

Accepted Answer

The answer of The ____________________ approximation is an alternative to...

Question 7

Production Line
A quality control inspector keeps a tally sheet of the number of acceptable and unacceptable products that come off two different production lines.The completed sheet is shown below. $$\begin{array}{l}
\text { Products }\
\begin{array} { | c | c c | } 
\hline \text { Production line } & \text { Acceptable } & \text { Unacceptable } \
\hline 1 & 152 & 48 \
2 & 136 & 54 \
\hline
\end{array}
\end{array}$$
What is the p-value of the test?

Accepted Answer

The answer of Production Line
A quality control inspector keeps a...

Question 8

A test that we can use to determine whether two population variances are equal is the ____________________.

Accepted Answer

The answer of A test that we can use to...

Question 9

We say samples are ____________________ when the selection process for one is related to the selection process for the other.

Accepted Answer

The answer of We say samples are ____________________ when the...

Question 10

Automotive parts
A regional automotive parts chain store firm wants to improve the sales of tune-up supplies.It believes that a TV ad with a popular local,but offbeat,know-it-all actor might be able to affect their sales.Before the ads are run on TV,the company randomly samples eight of its weekly sales from past years.Following the ad campaign,eight weeks of sales were sampled.Weekly sales are approximately normally distributed and the population standard deviations are equal.Their hypothesis test is: Did the TV ad campaign help or hurt sales? To answer this question,the company plans to use a 0.05 significance level.The results of the two samples are: $$\begin{array} { | c | c | } 
\hline \text { Before Ad Campaign } & \text { After Ad Campaign } \
\hline n _ { 1 } = 8 & n _ { 2 } = 8 \
\bar { x } _ { 1 } = 184 & \bar { x } _ { 2 } = 189 \
s _ { 1 } ^ { 2 } = 548 & s _ { 2 } ^ { 2 } = 456 \
\hline
\end{array}$$
-What is the test statistic?
Appropriate test: ____________________
Test statistic = ____________________

Accepted Answer

The answer of Automotive parts
A regional automotive parts chain store...

Question 11

Automotive parts
A regional automotive parts chain store firm wants to improve the sales of tune-up supplies.It believes that a TV ad with a popular local,but offbeat,know-it-all actor might be able to affect their sales.Before the ads are run on TV,the company randomly samples eight of its weekly sales from past years.Following the ad campaign,eight weeks of sales were sampled.Weekly sales are approximately normally distributed and the population standard deviations are equal.Their hypothesis test is: Did the TV ad campaign help or hurt sales? To answer this question,the company plans to use a 0.05 significance level.The results of the two samples are: $$\begin{array} { | c | c | } 
\hline \text { Before Ad Campaign } & \text { After Ad Campaign } \
\hline n _ { 1 } = 8 & n _ { 2 } = 8 \
\bar { x } _ { 1 } = 184 & \bar { x } _ { 2 } = 189 \
s _ { 1 } ^ { 2 } = 548 & s _ { 2 } ^ { 2 } = 456 \
\hline
\end{array}$$
-What is the conclusion?

Accepted Answer

The answer of Automotive parts
A regional automotive parts chain store...

Question 12

Price earnings
A comparison of the price-earnings (P/E)ratio for the top and bottom 100 companies in valuation is being prepared.A financial advisor randomly sampled each group to determine whether there is any difference in P/E ratios of the two groups of companies.Let 1 = a top 100 company and 2 = a bottom 100 company.Assume equal population variances and that the populations are normally distributed.The advisor is to use a 0.01 significance level.The data were randomly selected and are summarized below: $$\begin{array} { | c | c | } 
\hline \text { Top 100 company } & \text { Bottom 100 company } \
\hline n _ { 1 } = 6 & n _ { 2 } = 6 \
\bar { x } _ { 1 } = 18.83 & \bar { x } _ { 2 } = 10.67 \
s _ { 1 } ^ { 2 } = 128.17 & s _ { 2 } ^ { 2 } = 8.67 \
\hline
\end{array}$$
-What is the value of the test statistic?
Appropriate test: ____________________
Test statistic = ____________________

Accepted Answer

The answer of Price earnings
A comparison of the price-earnings (P/E)ratio...

Question 13

Medicare
An economist wishes to test whether there is any difference in the proportion of households receiving Medicare for white households with less than $5,000 income per year and white households with $15,000 or more income per year.A random sample from households with less than $5,000 income per year is taken,and a random sample of households with $15,000 or more income is taken.The results of the samples are: $$\begin{array} { | l | c c | } 
\hline & \text { Less than } \$ \mathbf { 5 , 0 0 0 } & \mathbf { \$ 1 5 , 0 0 0 } \text { or more } \
\hline \text { Sample size } & 200 & 150 \
\text { Medicare Recipients } & 157 & 139 \
\hline
\end{array}$$
Use a 0.01 significance level to determine if there is sufficient evidence to conclude that a difference in proportions exists.Calculate the standard error of estimate.

Accepted Answer

The answer of Medicare
An economist wishes to test whether there...

Question 14

Automotive parts A regional automotive parts chain store firm wants to improve the sales of tune-up supplies.It believes that a TV ad with a popular local,but offbeat,know-it-all actor might be able to affect their sales.Before the ads are run on TV,the company randomly samples eight of its weekly sales from past years.Following the ad campaign,eight weeks of sales were sampled.Weekly sales are approximately normally distributed and the population standard deviations are equal.Their hypothesis test is: Did the TV ad campaign help or hurt sales? To answer this question,the company plans to use a 0.05 significance level.The results of the two samples are: $$\begin{array} { | c | c | } \hline \text { Before Ad Campaign } & \text { After Ad Campaign } \ \hline n _ { 1 } = 8 & n _ { 2 } = 8 \ \bar { x } _ { 1 } = 184 & \bar { x } _ { 2 } = 189 \ s _ { 1 } ^ { 2 } = 548 & s _ { 2 } ^ { 2 } = 456 \ \hline \end{array}$$ -State null and alternative hypotheses. H₀: ____________________ H₁: ____________________

Accepted Answer

The answer of Automotive parts
A regional automotive parts chain store...

Question 15

Ford Motor Co.
The Ford Motor Company,as part of its quality control program,began returning to the supplier all shipments of steel that had defects or faulty chemistry.When Ford began this program,the defective rate in 100 shipments was 9%.A recent survey indicated that 2.2% in 136 shipments was defective.Does this represent a significant improvement in the quality of the steel? Test at the 0.05 level.
What is the p-value?

Accepted Answer

The answer of Ford Motor Co.
The Ford Motor Company,as part...

Question 16

Automotive parts
A regional automotive parts chain store firm wants to improve the sales of tune-up supplies.It believes that a TV ad with a popular local,but offbeat,know-it-all actor might be able to affect their sales.Before the ads are run on TV,the company randomly samples eight of its weekly sales from past years.Following the ad campaign,eight weeks of sales were sampled.Weekly sales are approximately normally distributed and the population standard deviations are equal.Their hypothesis test is: Did the TV ad campaign help or hurt sales? To answer this question,the company plans to use a 0.05 significance level.The results of the two samples are: $$\begin{array} { | c | c | } 
\hline \text { Before Ad Campaign } & \text { After Ad Campaign } \
\hline n _ { 1 } = 8 & n _ { 2 } = 8 \
\bar { x } _ { 1 } = 184 & \bar { x } _ { 2 } = 189 \
s _ { 1 } ^ { 2 } = 548 & s _ { 2 } ^ { 2 } = 456 \
\hline
\end{array}$$
-What is the decision rule?

Accepted Answer

The answer of Automotive parts
A regional automotive parts chain store...

Question 17

Battery
A new brand of battery for use in calculators and cameras is said to last significantly longer than another brand.A camera manufacturer is to test this brand (Y)with brand (X)to see if brand Y has a longer life.If brand Y does last longer,the camera manufacturer will equip their new cameras with them.If not,they will equip them with brand X that is less costly.Twenty cameras are equipped as follows: ten with brand Y batteries and ten with brand X batteries and the life of the batteries measured.Is brand Y superior (does it last longer)to brand X? To answer this question,the camera manufacturer uses a 0.01 significance level and knows that the populations are normally distributed with equal variances.Sample data are: $$\begin{array} { | c | c | } 
\hline \text { Brand } \boldsymbol { X } & \text { Brand } \boldsymbol { Y } \
\hline n _ { 1 } = 10 & n _ { 2 } = 10 \
\bar { x } _ { 1 } = 500 \text { hours } & \bar { x } _ { 2 } = 650 \text { hours } \
s _ { 1 } ^ { 2 } = 400 & s _ { 2 } ^ { 2 } = 484 \
\hline
\end{array}$$
-What is the test statistic?
Appropriate test: ____________________
Test statistic = ____________________

Accepted Answer

The answer of Battery
A new brand of battery for use...

Question 18

Tests in which samples are not independent are referred to as ______________________________.

Accepted Answer

The answer of Tests in which samples are not independent...

Question 19

Price earnings A comparison of the price-earnings (P/E)ratio for the top and bottom 100 companies in valuation is being prepared.A financial advisor randomly sampled each group to determine whether there is any difference in P/E ratios of the two groups of companies.Let 1 = a top 100 company and 2 = a bottom 100 company.Assume equal population variances and that the populations are normally distributed.The advisor is to use a 0.01 significance level.The data were randomly selected and are summarized below: $$\begin{array} { | c | c | } \hline \text { Top 100 company } & \text { Bottom 100 company } \ \hline n _ { 1 } = 6 & n _ { 2 } = 6 \ \bar { x } _ { 1 } = 18.83 & \bar { x } _ { 2 } = 10.67 \ s _ { 1 } ^ { 2 } = 128.17 & s _ { 2 } ^ { 2 } = 8.67 \ \hline \end{array}$$ -State the null and alternative hypotheses. H₀: ____________________ H₁: ____________________

Accepted Answer

The answer of Price earnings
A comparison of the price-earnings (P/E)ratio...

Question 20

____________________ samples are those for which the selection process for one is not related to the selection process for the other.

Accepted Answer

The answer of ____________________ samples are those for which the...

Quiz 11: Hypothesis Tests Involving Two Sample Means

The pooled-variances t-test requires the assumption that the two population _ are equal,and that the populations are at least _ distributed.

When comparing the means of two independent samples,the ____________________ is applicable whenever the population standard deviations are unknown.

The ____________________ approximation is an alternative to the unequal-variances t-test whenever both n₁ and n₂ are ≥ 30.

A test that we can use to determine whether two population variances are equal is the ____________________.

We say samples are ____________________ when the selection process for one is related to the selection process for the other.

Tests in which samples are not independent are referred to as ______________________________.

____________________ samples are those for which the selection process for one is not related to the selection process for the other.

Quiz 11: Hypothesis Tests Involving Two Sample Means

The pooled-variances t-test requires the assumption that the two population ___________________________________ are equal,and that the populations are at least ___________________________________ distributed.

When comparing the means of two independent samples,the ____________________ is applicable whenever the population standard deviations are unknown.

The ____________________ approximation is an alternative to the unequal-variances t-test whenever both n1 and n2 are ≥ 30.

A test that we can use to determine whether two population variances are equal is the ____________________.

We say samples are ____________________ when the selection process for one is related to the selection process for the other.

Tests in which samples are not independent are referred to as ______________________________.

____________________ samples are those for which the selection process for one is not related to the selection process for the other.

The pooled-variances t-test requires the assumption that the two population _ are equal,and that the populations are at least _ distributed.

The ____________________ approximation is an alternative to the unequal-variances t-test whenever both n₁ and n₂ are ≥ 30.