A researcher is estimating the average difference between two population means based on matched-pairs samples.She gathers data on each pair in the study resulting in: \[\begin{array} { | l | l | l | } \hline \text { Pair } & \text { Group 1 } & \text { Group 2 } \\ \hline 1 & 10 & 12 \\ \hline 2 & 8 & 9 \\ \hline 3 & 11 & 11 \\ \hline 4 & 8 & 10 \\ \hline 5 & 9 & 12 \\ \hline \end{array}\] Assume that the data are normally distributed in the population.To obtain a 90% confidence interval, the table t value would be _______.

A) 1.86 B) 1.397 C) 1.533 D) 2.132 E) 3.346 A) 1.86 B) 1.397 C) 1.533 D) 2.132 E) 3.346

A researcher is estimating the average difference between two population means based on matched-pairs samples.She gathers data on each pair in the study resulting in: \[\begin{array} { | r | r | r | } \hline {\text { Pair } } & \text { Group 1 } & \text { Group } 2 \\ \hline 1 & 10 & 12 \\ \hline 2 & 8 & 9 \\ \hline 3 & 11 & 11 \\ \hline 4 & 8 & 10 \\ \hline 5 & 9 & 12 \\ \hline \end{array}\] Assume that the data are normally distributed in the population.A 95% confidence interval would be _______.

A) -3.02 to -0.18 B) -1.6 to -1.09 C) -2.11 to 1.09 D) -2.11 to -1.09 E) -3.23 to 2.23 A) -3.02 to -0.18 B) -1.6 to -1.09 C) -2.11 to 1.09 D) -2.11 to -1.09 E) -3.23 to 2.23

A researcher is conducting a matched-pairs study.She gathers data on each pair in the study resulting in: \[\begin{array} { | c | c | c | } \hline \text { Pair } & \text { Group 1 } & \text { Group } 2 \\ \hline 1 & 10 & 12 \\ \hline 2 & 8 & 9 \\ \hline 3 & 11 & 11 \\ \hline 4 & 8 & 10 \\ \hline 5 & 9 & 12 \\ \hline \end{array}\] Assume that the data are normally distributed in the population.The sample standard deviation (sd)of the differences is _______.

A) 1.30 B) 1.14 C) 1.04 D) 1.02 E) 1.47 A) 1.30 B) 1.14 C) 1.04 D) 1.02 E) 1.47

Exam 10: Statistical Inferences About Two Populations

Collinsville Construction Company purchases steel rods for its projects.Based on previous tests, Claude Carter, Quality Assurance Manager, has recommended not purchasing rods from Redding Rods, Inc.(population 1), and switching to Stockton Steel (population 2), since Stockton's rods had less variability in length.Claude has sampled the outputs from Redding's and Stockton's rod manufacturing processes.The results for Redding were s₁² = 0.10 with n₁ = 8, and, for Stockton, the results were s₂² = 0.05 with n₂ = 10.Assume that rod lengths are normally distributed in the population.If $\alpha$ = 0.05, the observed F value is ___________.

(Multiple Choice)

4.7/5

(35)

Question 21

Maureen McIlvoy, owner and CEO of a mail order business for wind surfing equipment and supplies, is reviewing the order filling operations at her warehouses.Her goal is 100% of orders shipped within 24 hours.In previous years, neither warehouse has achieved the goal, but the West Coast Warehouse has consistently out-performed the East Coast Warehouse.Her staff randomly selected 200 orders from the West Coast Warehouse (population 1)and 400 orders from the East Coast Warehouse (population 2), and reports that 190 of the West Coast Orders were shipped within 24 hours, and the East Coast Warehouse shipped 372 orders within 24 hours.Assuming $\alpha$ = 0.05, the observed z value is ___________________.

(Multiple Choice)

4.9/5

(33)

Question 22

If the populations are normally distributed but the population variances are unknown the z-statistic can be used as the basis for statistical inferences about the difference in two population means using two independent random samples.

(True/False)

4.7/5

(29)

Question 23

A researcher believes a new diet should improve weight gain.To test his hypothesis, a random sample of 10 people on the old diet and an independent random sample of 10 people on the new diet were selected.The selected people on the old diet gained an average of 5 pounds with a standard deviation of 2 pounds, while the average gain for selected people on the new diet was 8 pounds with a standard deviation of 1.5 pounds.Assuming that the values are normally distributed in each population, the researcher would like to use the t procedure with pooled standard deviation.To use this procedure, it must be shown that the variances from the two populations can be assumed to be equal.Using the sample data to test this assumption at $\alpha$ = 0.05, the observed F value is _______.

(Multiple Choice)

4.8/5

(34)

Question 24

A researcher is estimating the average difference between two population means based on matched-pairs samples.She gathers data on each pair in the study resulting in: Pair Group 1 Group 2 1 10 12 2 8 9 3 11 11 4 8 10 5 9 12 Assume that the data are normally distributed in the population.To obtain a 90% confidence interval, the table t value would be _______.

(Multiple Choice)

4.8/5

(37)

Question 25

A researcher is interested in testing to determine if the mean price of a casual lunch is different in the city than it is in the suburbs.The null hypothesis is that there is no difference in the population means (i.e.the difference is zero).The alternative hypothesis is that there is a difference (i.e.the difference is not equal to zero).He randomly selects a sample of 9 lunch tickets from the city population resulting in a mean of $14.30 and a standard deviation of $3.40.He randomly selects a sample of 14 lunch tickets from the suburban population resulting in a mean of $11.80 and a standard deviation $2.90.He is using an alpha value of .10 to conduct this test.Assuming that the populations are normally distributed, the critical t value from the table is _______.

(Multiple Choice)

5.0/5

(35)

Question 26

A researcher is estimating the average difference between two population means based on matched-pairs samples.She gathers data on each pair in the study resulting in: Pair Group 1 Group 2 1 10 12 2 8 9 3 11 11 4 8 10 5 9 12 Assume that the data are normally distributed in the population.A 95% confidence interval would be _______.

(Multiple Choice)

4.9/5

(41)

Question 27

The ratio of two independent sample variances follows the F distribution.

(True/False)

4.9/5

(42)

Question 28

The F test of two population variances is extremely robust to the violations of the assumption that the populations are normally distributed.

(True/False)

4.7/5

(34)

Question 29

Maxwell Cantor, VP of human resources of Asimov Aerospace Industries Inc., is reviewing the technical certifications of employees in different divisions of the company.His goal is to have at least 90% of technical employees with up-to-date certifications.The north-east division typically has maintained higher rates of up-to-date certifications than the southern division.He selects a random sample of 250 employees from the north-east division and 300 from the southern division and finds out that the number of employees with up-to-date certifications are 230 in the north-east division and 265 in the southern division.Assuming $\alpha$ = 0.01, the critical z value is ______.

(Multiple Choice)

4.9/5

(36)

Question 30

Maureen McIlvoy, owner and CEO of a mail order business for wind surfing equipment and supplies, is reviewing the order filling operations at her warehouses.Her goal is 100% of orders shipped within 24 hours.In previous years, neither warehouse has achieved the goal, but the West Coast Warehouse has consistently out-performed the East Coast Warehouse.Her staff randomly selected 200 orders from the West Coast Warehouse (population 1)and 400 orders from the East Coast Warehouse (population 2), and reports that 190 of the West Coast Orders were shipped within 24 hours, and the East Coast Warehouse shipped 372 orders within 24 hours.Assuming $\alpha$ = 0.05, the critical z value is ___________________.

(Multiple Choice)

4.8/5

(32)

Question 31

If the sample sizes are greater than 30 and the population variances are known, the basis for statistical inferences about the difference in two population means using two independent random samples is the z-statistic, regardless of the shapes of the population distributions.

(True/False)

4.9/5

(25)

Question 32

Tamara Hill, fund manager of the Hill Value Fund, manages a portfolio of 250 common stocks.Tamara is searching for a 'low risk' issue to add to the portfolio, i.e., one with a price variance less than that of the S&P 500 index.Moreover, she assumes an issue is not 'low risk' until demonstrated otherwise.Her staff reported that during the last nine quarters, the price variance for the S&P 500 index (population 1)was 25, and for the last seven quarters, the price variance for XYC common (population 2)was 6.Assume that stock prices are normally distributed in the population.Using $\alpha$ = 0.05, the appropriate decision is _______.

(Multiple Choice)

4.8/5

(35)

Question 33

A researcher is interested in estimating the difference in two population proportions.A sample of 400 from each population results in sample proportions of .61 and .64.The point estimate of the difference in the population proportions is _______.

(Multiple Choice)

4.9/5

(39)

Question 34

Collinsville Construction Company purchases steel rods for its projects.Based on previous tests, Claude Carter, Quality Assurance Manager, has recommended not purchasing rods from Redding Rods, Inc.(population 1), and switching to Stockton Steel (population 2), since Stockton's rods had less variability in length.Claude has sampled the outputs from Redding's and Stockton's rod manufacturing processes.The results for Redding were s₁² = 0.10 with n₁ = 8, and, for Stockton, the results were s₂² = 0.05 with n₂ = 10.Assume that rod lengths are normally distributed in the population.Claude's null hypothesis is ________________.

(Multiple Choice)

4.9/5

(28)

Question 35

In order to construct an interval estimate of the difference in the means of two normally distributed populations with unknown but equal variances, using two independent samples of size n₁ and n₂, we must use a t distribution with (n₁+ n₂− 2)degrees of freedom.

(True/False)

4.7/5

(45)

Question 36

A researcher is conducting a matched-pairs study.She gathers data on each pair in the study resulting in: Pair Group 1 Group 2 1 10 12 2 8 9 3 11 11 4 8 10 5 9 12 Assume that the data are normally distributed in the population.The sample standard deviation (s_d)of the differences is _______.

(Multiple Choice)

4.9/5

(26)

Question 37

Your company is evaluating two cloud-based, secured data storage services."Pie in the Sky," the newer service, claims its uploading and downloading speeds are faster than the older service, "Cloudy but Steady Skies." You need to make a decision based on published access times for both services at different times and for varying file sizes.Your alternative hypothesis is ______.

(Multiple Choice)

4.9/5

(43)

Question 38

If the populations are normally distributed and the variances of the two populations are equal, it is appropriate to use the "pooled" formula to determine the t-statistic for the hypothesis test of the difference in the two population means.

(True/False)

4.9/5

(26)

Question 39

Golf course designer Roberto Langabeer is evaluating two sites, Palmetto Dunes and Ocean Greens, for his next golf course.He wants to prove that Palmetto Dunes residents (population 1)play golf more often than Ocean Greens residents (population 2).Roberto plans to test this hypothesis using a random sample of 81 individuals from each suburb.His alternative hypothesis is __________.

(Multiple Choice)

4.8/5

(34)

Question 40

Showing 21 - 40 of 97

If the populations are normally distributed but the population variances are unknown the z-statistic can be used as the basis for statistical inferences about the difference in two population means using two independent random samples.

The ratio of two independent sample variances follows the F distribution.

The F test of two population variances is extremely robust to the violations of the assumption that the populations are normally distributed.

If the sample sizes are greater than 30 and the population variances are known, the basis for statistical inferences about the difference in two population means using two independent random samples is the z-statistic, regardless of the shapes of the population distributions.

A researcher is interested in estimating the difference in two population proportions.A sample of 400 from each population results in sample proportions of .61 and .64.The point estimate of the difference in the population proportions is _______.

In order to construct an interval estimate of the difference in the means of two normally distributed populations with unknown but equal variances, using two independent samples of size n₁ and n₂, we must use a t distribution with (n₁+ n₂− 2)degrees of freedom.

A researcher is conducting a matched-pairs study.She gathers data on each pair in the study resulting in: Pair Group 1 Group 2 1 10 12 2 8 9 3 11 11 4 8 10 5 9 12 Assume that the data are normally distributed in the population.The sample standard deviation (s_d)of the differences is _______.

If the populations are normally distributed and the variances of the two populations are equal, it is appropriate to use the "pooled" formula to determine the t-statistic for the hypothesis test of the difference in the two population means.

Introduction to Statistics and Business Analytics

Visualizing Data With Charts and Graphs

Descriptive Statistics

Probability

Discrete Distributions

Continuous Distributions

Sampling and Sampling Distributions

Statistical Inference: Estimation for Single Populations

Statistical Inference: Hypothesis Testing for Single Populations

Analysis of Variance and Design of Experiments

Simple Regression Analysis and Correlation

Multiple Regression Analysis

Building Multiple Regression Models

Time-Series Forecasting and Index Numbers

Analysis of Categorical Data

Nonparametric Statistics

Statistical Quality Control

Decision Analysis

Filters

Exam 10: Statistical Inferences About Two Populations

If the populations are normally distributed but the population variances are unknown the z-statistic can be used as the basis for statistical inferences about the difference in two population means using two independent random samples.

The ratio of two independent sample variances follows the F distribution.

The F test of two population variances is extremely robust to the violations of the assumption that the populations are normally distributed.

If the sample sizes are greater than 30 and the population variances are known, the basis for statistical inferences about the difference in two population means using two independent random samples is the z-statistic, regardless of the shapes of the population distributions.

A researcher is interested in estimating the difference in two population proportions.A sample of 400 from each population results in sample proportions of .61 and .64.The point estimate of the difference in the population proportions is _______.

In order to construct an interval estimate of the difference in the means of two normally distributed populations with unknown but equal variances, using two independent samples of size n1 and n2, we must use a t distribution with (n1 + n2 − 2)degrees of freedom.

A researcher is conducting a matched-pairs study.She gathers data on each pair in the study resulting in: Pair Group 1 Group 2 1 10 12 2 8 9 3 11 11 4 8 10 5 9 12 Assume that the data are normally distributed in the population.The sample standard deviation (sd)of the differences is _______.

If the populations are normally distributed and the variances of the two populations are equal, it is appropriate to use the "pooled" formula to determine the t-statistic for the hypothesis test of the difference in the two population means.

Introduction to Statistics and Business Analytics

Visualizing Data With Charts and Graphs

Descriptive Statistics

Probability

Discrete Distributions

Continuous Distributions

Sampling and Sampling Distributions

Statistical Inference: Estimation for Single Populations

Statistical Inference: Hypothesis Testing for Single Populations

Analysis of Variance and Design of Experiments

Simple Regression Analysis and Correlation

Multiple Regression Analysis

Building Multiple Regression Models

Time-Series Forecasting and Index Numbers

Analysis of Categorical Data

Nonparametric Statistics

Statistical Quality Control

Decision Analysis

Filters

In order to construct an interval estimate of the difference in the means of two normally distributed populations with unknown but equal variances, using two independent samples of size n₁ and n₂, we must use a t distribution with (n₁+ n₂− 2)degrees of freedom.

A researcher is conducting a matched-pairs study.She gathers data on each pair in the study resulting in: Pair Group 1 Group 2 1 10 12 2 8 9 3 11 11 4 8 10 5 9 12 Assume that the data are normally distributed in the population.The sample standard deviation (s_d)of the differences is _______.