Managers of an industrial plant want to determine which of two types of fuel, gas or electric, is more cost efficient (measured in cost per unit of energy).Independent random samples were taken of plants using electricity and plants using gas. These samples consisted of 11 plants using electricity, which had amean cost per unit of $45.60 and standard deviation of $8.46, and 16 plants using gas, which had a mean of $48.40 and standard deviation of $8.36. Assumethat the populations of costs per unit are normally distributed for each type of fuel, and assume that the variances of these populations are equal. Construct a99% confidence interval for the difference µ, -µ, between the mean cost per unit for plants using electricity, u,, and the mean cost per unit for plants usinggas, µ,. Then find the lower limit and upper limit of the 99% confidence interval.Carry your intermediate computations to at least three decimal places. Round your responses to at least two decimal places. (If necessary, consult a list offormulas.)Lower limit:|Upper limit:

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Answered: Managers of an industrial plant want to…

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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An amusement park conducted an internal audit on the wait times of its customers for the park's rides during a summer weekend. The audit found that the wait times of customers for the Shooting Star ride had a population mean of 31.2 minutes with a population variance of 6.3 minutes The park's head executive has doubts about the audit's findings concerning the Shooting Star ride. He hires an inspector to check these findings. On a summer weekend, the inspector takes a sample of 12 people at random waiting in line for the Shooting Star. She records their wait times and finds that the sample mean is 33.1 minutes and the sample variance is 4.8 minutes 2 Fill in the blanks below with the proper notation for the population mean, the population variance, and the sample variance. 66°F Cloudy Population mean: (Choose one) = 31.2 minutes X Population variance: (Choose one) = 6.3 minutes 2 Sample variance: (Choose one) 2 = 4.8 minutes Continue 3 W E 5. D DIL R Q Search 5 G 7 G Y U H 8 X C V B N M…
Research has shown that, for baseball players, good hip range of motion results in improved performance and decreased body stress. A research article reported on a study of independent samples of 40 professional pitchers and 40 professional position players. For the pitchers, the sample mean hip range of motion was 75.5 degrees and the sample standard deviation was 5.8 degrees, whereas the sample mean and sample standard deviation for position players were 79.1 degrees and 7.1 degrees, respectively. Assuming that the two samples are representative of professional baseball pitchers and position players, test hypotheses appropriate for determining if there is convincing evidence that the mean range of motion for pitchers is less than the mean for position players. (Use ? = 0.05. Use ?1 for pitchers and ?2 for position players.) State the appropriate null and alternative hypotheses. Find the test statistic and P-value. (Use SALT. Round your test statistic to one decimal place and…
In a test of the effectiveness of garlic for lowering cholesterol, 36 subjects were treated with raw garlic Cholesterol levels were measured before and after the treatment. The changes (before minus after) in their levels of LDL cholesterol (in mg/dL) have a mean of 0.1 and a standard deviation of 23.2. Use a 0.01 significance level to test the claim that with garlic treatment, the mean change in LDL cholesterol is greater than 0. What do the results suggest about the effectiveness of the garlic treatment? Assume that a simple random sample has been selected. Identify the null and alternative hypotheses, test statistic, P-value, and state the final conclusion that addresses the original claim. What are the null and alternative hypotheses? O A. Ho p=0 mg/dL O B. H, p=0mg/dL H, p0 mg/dL OC. Ho H>0 mg/dL O D. H, p=0 mg/dL. H, pz0 mg/dL. H, p<0 mg/dL
A veterinarian wants to perform a study at a local animal shelter where 200 dogs need training on behavior modification. The purpose of the study would be to determine if using a firm voice during training for 10 minutes improves a dog's learning behavior compared to not speaking during training for 10 minutes. Part A: Describe an appropriate design for the study. Part B: The hypotheses for this study are as follows: Ho: There is no difference in the mean improvement of dogs during behavior modification for either treatment. Ha: The mean improvement of dogs during behavior modification is greater for the firm voice treatment. The shelters will allow trainers to use a firm voice during training if the null hypothesis is rejected. What are the possible Type I and II errors? Describe the consequences of each in the context of this study and discuss which type you think is more serious.n
The Airline Passenger Association studied the relationship between the number of passengers on a particular flight and the cost of the flight. It seems logical that more passengers on the flight will result in more weight and more luaggage, which in turn will result in higher fuel costs. For a sample of 13 flights, the correlation between the number of passengers and total fuel cost was .37. Is it reasonable to conclude that there is positive association in the population between the two variables? H0: p≤0 Ha: p >0 Use the 5% significant level, what is the p-value?____________ What is your decision regarding H0 or the hull hypothesis? Reject or Do not Reject______________ Draw a conclusion. Specifically, what does this indicate about the question?
An experiment was conducted to compare the yield of three plant genotypes. The height of plants was also recorded to serve as concomitant variable. 1. Determine if each of the statemen is true or false regarding to test of linear dependence between height and genotype at a=0.05 a. There is sufficient evidence that at least one genotype has a different mean plant height. b. It was found that the height and genotype of the plants are independent. 2. Determine if each of the statemen is true or false regarding to test of the linear dependence of yield on height at a=0.05. a. Plant height is not an effective concomitant variable for the experiment. b. There is sufficient evidence that plant yield is linearly dependent on height. 3. Assuming that assumptions of ANCAOVA were satisfied, determine if each statement is true or falsewith regards to test of significnace of genotype effects using ANACAOVA a=0.05 a. There is sufficient evidence that at least one genotype has a different mean plant…
To determine if there is gender and/or race discrimination in car buying, a researcher put together a team of white males, black males, white females, and black females who were each asked to obtain an initial offer price from the dealer on a certain model car. The accompanying data are based on the results and represent the profit on the initial price offered by the dealer. Previous testing resulted in rejecting Ho: PWM HBM =HWF = HBF and concluding that the mean profit for the four race-gender groups differ. Use Tukey's test to determine which pairwise means differ using a familywise error rate of a = 0.05. Click the icon to view the data table. Use Tukey's test to determine which pairwise means differ using a familywise error rate of a = 0.05. Find the Tukey 95% simultaneous confidence intervals for all pairwise comparisons. The interval for the pairwise comparision HBM HWM is The interval for the pairwise comparision pwFPWM is The interval for the pairwise comparision HBF HWM is…
A study was conducted using 50 mobile network users who volunteered to participate in a research as the entry of the third telco player in the country is on its way. One of the variables studied was the data connection speed in the previous month. Based on the data in the following table, is there a significant difference between the connectivity speeds of the two present mobile networks during the previous month? Use a 5% level of significance and assume that the population variances are equal. 1. The alternative hypothesis for the test would be? 2. The alternative hypothesis for the test would be? 3. What is the computed value of the test statistic? 4. What would be your decision?
Use the following information to answer the question. A researcher wants to study different messaging platforms by collecting data on 40 individuals. Half of the individuals only use iMessage while the other half only use What's App. For the individuals who only used iMessage, they sent an average of 280 messages with a sample variance of 170 in the past week. For the individuals who only used What's App, they sent an average of 295 messages with a sample variance of 182 in the past week. Determine if there is a significant difference between the average messages sent between the two groups of individuals. Use a significance level of 1%. What is the null hypothesis? Group of answer choices A. The iMessage group on average sent more messages than the What's App group. B. The iMessage group on average sent less messages than the What's App group. C. There is no difference in the average number of messages sent between the two groups. D. There is a difference in the average…
Ackerman and Goldsmith (2011) found that students who studied text from printed hardcopy had better test scores than students who studied text presented on the screen. In a related study, a professor noticed that several students in a large class had purchased the e-book version of the course textbook. For the final exam, the overall average for the entire class was μ= 81.7, but the sample of n = 9 students who used e-books had a mean of M = 77.2 with ((SS =392) Is the sample sufficient to conclude that scores for students using e-books were sufficiently different from scores for the regular class? Use a two-tail test with α= .01.(not .05). Please answer the question using all of the steps presented on your practice problem assignment. (null in word, alternative in words, null in symbols, alternative in symbols, critical region t, df, all steps in the analysis computing your computed t, make a decision, and give a conclusion.
7.21 Facial structure of CEOS. In Psychological Science (Vol. 22, 2011), researchers reported that a chief executive officer's facial structure can be used to predict a firm's financial performance. The study involved measuring the facial width-to-height ratio (WHR) for each in a sample of 55 CEOS at publicly traded Fortune 500 firms. These WHR values (determined by computer analyzing a photo of the CEO's face) had a mean ofY = 1.96 and a standard deviation of s = .15. a. Find and interpret a 95% confidence interval for µ, the mean facial WHR for all CEOS at publicly traded Fortune 500 firms b. The researchers found that CEOS with wider faces (relative to height) tended to be associated with firms that had greater financial performance. They based their inference on an equation that uses facial WHR to pre- dict financial performance. Suppose an analyst wants to predict the financial performance of a Fortune 500 firm based on the value of the true mean facial WHR of CEOS The analyst…
A technician compares repair costs for two types of microwave ovens (type I and type II). He believes that the repair cost for type I ovens is greater than the repair cost for type II ovens. A sample of 35 type I ovens has a mean repair cost of $80.39. The population standard deviation for the repair of type I ovens is known to be $24.63. A sample of 31 type II ovens has a mean repair cost of $73.47. The population standard deviation for the repair of type II ovens is known to be $10.42. Conduct a hypothesis test of the technician's claim at the 0.05 level of significance. Let i be the true mean repair cost for type I ovens and µz be the true mean repair cost for type II ovens. Step 1 of 5: State the null and alternative hypotheses for the test.

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