The following information was obtained from independent random samples taken of two populations. Assume normally distributed populations with equal variances. \[\begin{array} { l l l } & \text { Sample 1 } & \text { Sample 2 } \\ \text { Sample Mean } & 45 & 42 \\ \text { Sample Variance } & 85 & 90 \\ \text { Sample Size } & 10 & 12 \end{array}\] The degrees of freedom for the t distribution are

A) 22. B) 21. C) 24. D) 20. A) 22. B) 21. C) 24. D) 20.

In testing the null hypothesis H0: = 0, the computed test statistic is z = -1.66.The corresponding p-value is?

A) .0485. B) .0970. C) .9515. D) .9030. A) .0485. B) .0970. C) .9515. D) .9030.

The results of a recent poll on the preference of shoppers regarding two products are shown below. \[\begin{array} { l l l } \text { Product } & \text { Shoppers Surveyed } & \text { Shoppers Favoring } \\ & & \text { This Product } \\ \text { A } & 800 & 560 \\ \text { B } &900 & 612 \end{array}\] The point estimate for the difference between the two population proportions in favor of this product is

A) .07. B) .68. C) .44. D) .02. A) .07. B) .68. C) .44. D) .02.

The following information was obtained from independent random samples taken of two populations. Assume normally distributed populations with equal variances. \[\begin{array} { l l l } & \text { Sample 1 } & \text { Sample 2 } \\ \text { Sample Mean } & 45 & 42 \\ \text { Sample Variance } & 85 & 90 \\ \text { Sample Size } & 10 & 12 \end{array}\] The 95% confidence interval for the difference between the two population means is (use rounded standard error)

A) -5.344 to 11.344. B) -5 to 3. C) -4.86 to 10.86. D) -2.65 to 8.65. A) -5.344 to 11.344. B) -5 to 3. C) -4.86 to 10.86. D) -2.65 to 8.65.

Salary information regarding male and female employees of a large company is shown below. \[\begin{array} { l r r } & \text { Male } & \text { Female } \\ \text { Sample Size } & 64 & 36 \\ \text { Sample Mean Salary } ( \text { in } \$ 1000 ) & 44 & 41 \\ \text { Population Variance } \left( \sigma ^ { 2 } \right)& 128 & 72 \end{array}\] The 95% confidence interval for the difference between the means of the two populations is

A) 0 to 6.92. B) -2 to 2. C) -1.96 to 1.96. D) -.92 to 6.92. A) 0 to 6.92. B) -2 to 2. C) -1.96 to 1.96. D) -.92 to 6.92.

An insurance company selected samples of clients under 18 years of age and over 18 and recorded the number of accidents they had in the previous year.The results are shown below. $\begin{array}{ll} \text { Under Age of } 18 & \text { Over Age of } 18 \\ n_{1}=500 & n_{2}=600 \\ \text { Number of accidents }=180 & \text { Number of accidents }=150 \end{array}$ We are interested in determining if the accident proportions differ between the two age groups. The pooled estimator of the population proportion is

A) .305. B) .300. C) .027. D) .450. A) .305. B) .300. C) .027. D) .450.

Salary information regarding male and female employees of a large company is shown below. \[\begin{array} { l r r } & \text { Male } & \text { Female } \\ \text { Sample Size } & 64 & 36 \\ \text { Sample Mean Salary } ( \text { in } \$ 1000 ) & 44 & 41 \\ \text { Population Variance } \left( \sigma ^ { 2 } \right)& 128 & 72 \end{array}\] If you are interested in testing whether or not the population average salary of males is significantly greater than that of females, the test statistic is

A) 2.0. B) 1.5. C) 1.96. D) 1.645. A) 2.0. B) 1.5. C) 1.96. D) 1.645.

In order to estimate the difference between the average hourly wages of employees of two branches of a department store, the following data have been gathered. $\begin{array}{lll} & \text { Downtown Store } & \text { North Mall Store } \\ \text { Sample size } & 25 & 20 \\ \text { Sample mean }& \$ 9 & \$ 8 \\ \text { Sample standard deviation } & \$ 2 & \$ 1 \end{array}$ A 95% interval estimate for the difference between the two population means is

A) .071 to 1.929. B) .226 to 1.774. C) 1.09 to 4.078. D) 1.078 to 2.922. A) .071 to 1.929. B) .226 to 1.774. C) 1.09 to 4.078. D) 1.078 to 2.922.

Salary information regarding male and female employees of a large company is shown below. \[\begin{array} { l r r } & \text { Male } & \text { Female } \\ \text { Sample Size } & 64 & 36 \\ \text { Sample Mean Salary } ( \text { in } \$ 1000 ) & 44 & 41 \\ \text { Population Variance } \left( \sigma ^ { 2 } \right)& 128 & 72 \end{array}\] At 95% confidence, the margin of error is

A) 1.960. B) 1.645. C) 3.920. D) 2.000. A) 1.960. B) 1.645. C) 3.920. D) 2.000.

Exam 10: Inference About Means and Proportions With Two Populations

Regarding inferences about the difference between two population means, the sampling design that uses a pooled sample variance in cases of equal population standard deviations is based on

(Multiple Choice)

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Question 21

The sampling distribution of $\bar { p } _ { 1 }$ - $\bar { p } _ { 2 }$ is approximated by a

(Multiple Choice)

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Question 22

The following information was obtained from matched samples taken from two populations. The daily production rates for a sample of workers before and after a training program are shown below.Assume the population of differences is normally distributed. Worker Before After 1 20 22 2 25 23 3 27 27 4 23 20 5 22 25 6 20 19 7 17 18 The point estimate for the difference between the means of the two populations is

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Question 23

The following information was obtained from independent random samples taken of two populations. Assume normally distributed populations with equal variances. Sample 1 Sample 2 Sample Mean 45 42 Sample Variance 85 90 Sample Size 10 12 The degrees of freedom for the t distribution are

(Multiple Choice)

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Question 24

A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago.A sample of final examination scores from students enrolled today and from students enrolled five years ago was taken.You are given the following information. Today Five Years Ago 82 88 112.5 54 n 45 36 The standard error of $\bar { x } _ { 1 }$ - $\bar { x } _ { 2 }$ is

(Multiple Choice)

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Question 25

In testing the null hypothesis H₀: = 0, the computed test statistic is z = -1.66.The corresponding p-value is?

(Multiple Choice)

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Question 26

The results of a recent poll on the preference of shoppers regarding two products are shown below. Product Shoppers Surveyed Shoppers Favoring This Product A 800 560 B 900 612 The point estimate for the difference between the two population proportions in favor of this product is

(Multiple Choice)

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Question 27

The following information was obtained from independent random samples taken of two populations. Assume normally distributed populations with equal variances. Sample 1 Sample 2 Sample Mean 45 42 Sample Variance 85 90 Sample Size 10 12 The 95% confidence interval for the difference between the two population means is (use rounded standard error)

(Multiple Choice)

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Question 28

Salary information regarding male and female employees of a large company is shown below. Male Female Sample Size 64 36 Sample Mean Salary ( in \ 1000) 44 41 Population Variance 128 72 The 95% confidence interval for the difference between the means of the two populations is

(Multiple Choice)

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Question 29

The following information was obtained from matched samples taken from two populations. The daily production rates for a sample of workers before and after a training program are shown below.Assume the population of differences is normally distributed. Worker Before After 1 20 22 2 25 23 3 27 27 4 23 20 5 22 25 6 20 19 7 17 18 The null hypothesis to be tested is H₀: $\mu$ d = 0.The test statistic is

(Multiple Choice)

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Question 30

An insurance company selected samples of clients under 18 years of age and over 18 and recorded the number of accidents they had in the previous year.The results are shown below. Under Age of 18 Over Age of 18 =500 =600 Number of accidents =180 Number of accidents =150 We are interested in determining if the accident proportions differ between the two age groups. The pooled estimator of the population proportion is

(Multiple Choice)

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Question 31

Generally, the __ sample procedure for inferences about two population means provides better precision than the _ sample approach.

(Multiple Choice)

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Question 32

A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago.A sample of final examination scores from students enrolled today and from students enrolled five years ago was taken.You are given the following information. Today Five Years Ago 82 88 112.5 54 n 45 36 The point estimate for the difference between the means of the two populations is

(Multiple Choice)

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Question 33

Salary information regarding male and female employees of a large company is shown below. Male Female Sample Size 64 36 Sample Mean Salary ( in \ 1000) 44 41 Population Variance 128 72 If you are interested in testing whether or not the population average salary of males is significantly greater than that of females, the test statistic is

(Multiple Choice)

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Question 34

A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago.A sample of final examination scores from students enrolled today and from students enrolled five years ago was taken.You are given the following information. Today Five Years Ago 82 88 112.5 54 n 45 36 The p-value for the difference between the two population means is

(Multiple Choice)

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Question 35

In order to estimate the difference between the average hourly wages of employees of two branches of a department store, the following data have been gathered. Downtown Store North Mall Store Sample size 25 20 Sample mean \ 9 \ 8 Sample standard deviation \ 2 \ 1 A 95% interval estimate for the difference between the two population means is

(Multiple Choice)

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Question 36

Salary information regarding male and female employees of a large company is shown below. Male Female Sample Size 64 36 Sample Mean Salary ( in \ 1000) 44 41 Population Variance 128 72 At 95% confidence, the margin of error is

(Multiple Choice)

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Question 37

The following information was obtained from matched samples taken from two populations. The daily production rates for a sample of workers before and after a training program are shown below.Assume the population of differences is normally distributed. Worker Before After 1 20 22 2 25 23 3 27 27 4 23 20 5 22 25 6 20 19 7 17 18 Given that the null hypothesis to be tested is H₀: $\mu$ d = 0,

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Question 38

If we are interested in testing whether the proportion of items in population 1 is larger than the proportion of items in population 2, the

(Multiple Choice)

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Question 39

Two independent simple random samples are taken to test the difference between the means of two populations whose standard deviations are not known, but are assumed to be equal.The sample sizes are n₁ = 25 and n₂ = 35.The correct distribution to use is the

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Question 40

Regarding inferences about the difference between two population means, the sampling design that uses a pooled sample variance in cases of equal population standard deviations is based on

The sampling distribution of $\bar { p } _ { 1 }$ - $\bar { p } _ { 2 }$ is approximated by a

The following information was obtained from independent random samples taken of two populations. Assume normally distributed populations with equal variances. Sample 1 Sample 2 Sample Mean 45 42 Sample Variance 85 90 Sample Size 10 12 The degrees of freedom for the t distribution are

In testing the null hypothesis H₀: = 0, the computed test statistic is z = -1.66.The corresponding p-value is?

The results of a recent poll on the preference of shoppers regarding two products are shown below. Product Shoppers Surveyed Shoppers Favoring This Product A 800 560 B 900 612 The point estimate for the difference between the two population proportions in favor of this product is

Salary information regarding male and female employees of a large company is shown below. Male Female Sample Size 64 36 Sample Mean Salary ( in \ 1000) 44 41 Population Variance 128 72 The 95% confidence interval for the difference between the means of the two populations is

Generally, the __ sample procedure for inferences about two population means provides better precision than the _ sample approach.

Salary information regarding male and female employees of a large company is shown below. Male Female Sample Size 64 36 Sample Mean Salary ( in \ 1000) 44 41 Population Variance 128 72 At 95% confidence, the margin of error is

If we are interested in testing whether the proportion of items in population 1 is larger than the proportion of items in population 2, the

Two independent simple random samples are taken to test the difference between the means of two populations whose standard deviations are not known, but are assumed to be equal.The sample sizes are n₁ = 25 and n₂ = 35.The correct distribution to use is the

Data and Statistics

Descriptive Statistics: Tabulargraphical

Descriptive Statistics: Numerical

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

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Comparing Multiple Proportions, Test of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

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Exam 10: Inference About Means and Proportions With Two Populations

Regarding inferences about the difference between two population means, the sampling design that uses a pooled sample variance in cases of equal population standard deviations is based on

The sampling distribution of pˉ1\bar { p } _ { 1 }pˉ​1​ - pˉ2\bar { p } _ { 2 }pˉ​2​ is approximated by a

The following information was obtained from independent random samples taken of two populations. Assume normally distributed populations with equal variances. Sample 1 Sample 2 Sample Mean 45 42 Sample Variance 85 90 Sample Size 10 12 The degrees of freedom for the t distribution are

In testing the null hypothesis H0: = 0, the computed test statistic is z = -1.66.The corresponding p-value is?

The results of a recent poll on the preference of shoppers regarding two products are shown below. Product Shoppers Surveyed Shoppers Favoring This Product A 800 560 B 900 612 The point estimate for the difference between the two population proportions in favor of this product is

Salary information regarding male and female employees of a large company is shown below. Male Female Sample Size 64 36 Sample Mean Salary ( in \ 1000) 44 41 Population Variance 128 72 The 95% confidence interval for the difference between the means of the two populations is

Generally, the ________ sample procedure for inferences about two population means provides better precision than the _______ sample approach.​

Salary information regarding male and female employees of a large company is shown below. Male Female Sample Size 64 36 Sample Mean Salary ( in \ 1000) 44 41 Population Variance 128 72 At 95% confidence, the margin of error is

If we are interested in testing whether the proportion of items in population 1 is larger than the proportion of items in population 2, the

Two independent simple random samples are taken to test the difference between the means of two populations whose standard deviations are not known, but are assumed to be equal.The sample sizes are n1 = 25 and n2 = 35.The correct distribution to use is the

Data and Statistics

Descriptive Statistics: Tabulargraphical

Descriptive Statistics: Numerical

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Tests

Inferences About Population Variances

Comparing Multiple Proportions, Test of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

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The sampling distribution of $\bar { p } _ { 1 }$ - $\bar { p } _ { 2 }$ is approximated by a

In testing the null hypothesis H₀: = 0, the computed test statistic is z = -1.66.The corresponding p-value is?

Generally, the __ sample procedure for inferences about two population means provides better precision than the _ sample approach.

Two independent simple random samples are taken to test the difference between the means of two populations whose standard deviations are not known, but are assumed to be equal.The sample sizes are n₁ = 25 and n₂ = 35.The correct distribution to use is the