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 9 plants using electricity, which had a mean cost per unit of $50 and standard deviation of $8.58, and 15 plants using gas, which had a mean of $56.5 and standard deviation of $8.5. Assume that 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 a 99% confidence interval for the difference u,-H, between the mean cost per unit for plants using electricity, µ, and the mean cost per unit for plants using gas, µɔ. Then complete the table below. Carry your intermediate computations to at least three decimal places. Round your responses to at least two decimal places. (If necessary, consult a list of formulas.) What is the lower limit of the 99% confidence interval? What is the upper limit of the 99% confidence interval?

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 9 plants using electricity, which had a mean cost per unit of $50 and standard deviation of $8.58, and 15 plants using gas, which had a mean of $56.5 and standard deviation of $8.5. Assume that 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 a 99% confidence interval for the difference u,-H, between the mean cost per unit for plants using electricity, µ, and the mean cost per unit for plants using gas, µɔ. Then complete the table below. Carry your intermediate computations to at least three decimal places. Round your responses to at least two decimal places. (If necessary, consult a list of formulas.) What is the lower limit of the 99% confidence interval? What is the upper limit of the 99% confidence interval?

Name: Managers of an industrial plant want to determine which of two types
Uploaded: 2024-03-20T07:07:12.000Z
Channel: Bartleby
Description: 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. Thes

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

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 6060 type I ovens has a mean repair cost of $77.22$⁢77.22, with a standard deviation of $22.46$⁢22.46. A sample of 6565 type II ovens has a mean repair cost of $73.73$⁢73.73, with a standard deviation of $10.62$⁢10.62. Conduct a hypothesis test of the technician's claim at the 0.10.1 level of significance. Let μ1μ1 be the true mean repair cost for type I ovens and μ2μ2 be the true mean repair cost for type II ovens. Step 2 of 4 : Compute the value of the test statistic. Round your answer to two decimal places.
An industrial plant wants to determine which of two types of fuel, electric or gas, 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 7 plants using electricity, which had a mean cost per unit of $36.41 and standard deviation of $8.53, and 13 plants using gas, which had a mean of $46.50 and standard deviation of $8.60. Assume that the populations of costs per unit are normally distributed for each type of fuel, and assume that the variances of these populations are equal. Can we conclude, at the 0.10 level of significance, that u, the mean cost per unit for plants using electricity, differs from H,, the mean cost per unit for plants using gas? Perform a two-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified in the table. (If necessary, consult a list of formulas.)…
3. At a land farm, a farmer desired to test the effect of a given fertilizer on soybean production. He chose 24 plots of land of which are equal surface area. He treated 12 plots with the fertilizer and the others were untreated. Otherwise the conditions were the same. The treated plots produced soybean with mean yield 5.1 bushels and a standard deviation of 0.36 bushels, while the untreated plots had mean yield 4.8 bushels and a standard deviation of 0.40 bushels. (a) Can we conclude that there is a significant improvement in soybean production because of the fertilizer if a significance level of 1% is used? (b) What is the P-value of the test?
5. Dust mite allergies. Refer to Exercises 4.2 (p. 138) and 4.13 (p. 143). Each home with a dust mite level that ex- ceeds 2µg/g will spend $2,000 for an allergen air purifica- tion system. Find the mean and variance of the total amount spent by the four sampled homes. Give a range where this total is likely to fall.
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?
An industrial plant wants to determine which of two types of fuel, electric or gas, 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 14 plants using electricity, which had a mean cost per unit of $55.06 and standard deviation of $8.25, and 12 plants using gas, which had a mean of $57.80 and standard deviation of $7.81. Assume that the populations of costs per unit are normally distributed for each type of fuel, and assume that the variances of these populations are equal. Can we conclude, at the 0.10 level of significance, that μ₁, the mean cost per unit for plants using electricity, differs from μ₂, the mean cost per unit for plants using gas? Perform a two-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified in the table. (If necessary, consult a list of…
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…
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 10 plants using electricity, which had a mean cost per unit of $53.50 and standard deviation of $8.19 , and 11 plants using gas, which had a mean of $55.40 and standard deviation of $8.23 . Assume that 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 a 95% confidence interval for the difference −μ1μ2 between the mean cost per unit for plants using electricity, μ1 , and the mean cost per unit for plants using gas, μ2 . Then find the lower limit and upper limit of the 95% confidence interval. Carry your intermediate computations to at least three decimal places. Round your responses to at least…
The article “Well-Fed Crickets Bowl Maidens Over” (Nature Science Update, February 11, 1999) reported that female field crickets are attracted to males with high chirp rates and hypothesized that chirp rate is related to nutritional status. The usual chirp rate for male field crickets was reported to vary around a mean of 60 chirps per second. To investigate whether the chirp rate was related to nutritional status, investigators fed 22 male crickets a high protein diet for 8 days, after which chirp rate was measured. Let: The parameter μμ be the mean chirp rateof male crickets on a high protein diet for 8 days. Given: The mean chirp rate for the random sample of crickets on the high protein diet was reported to be 65.32 chirps per second with a standard deviation of 12. Research Question: Is there convincing evidence that the mean chirp rate for crickets on a high protein diet implies an advantage in attracting the ladies? It is known that the researchers did not want to…
An industrial plant wants to determine which of two types of fuel, electric or gas, 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 7 plants using electricity, which had a mean cost per unit of $64.13 and standard deviation of $8.32, and 12 plants using gas, which had a mean of $60.30 and standard deviation of $8.52. Assume that the populations of costs per unit are normally distributed for each type of fuel, and assume that the variances of these populations are equal. Can we conclude, at the 0.10 level of significance, that u,, the mean cost per unit for plants using electricity, differs from u, the mean cost per unit for plants using gas? Perform a two-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified in the table. (If necessary, consult a list of formulas.)…
atients suffering from rheumatic diseases or osteoporosis often suffer critical losses in bone mineral density (BMD). Alendronate is one medication prescribed to build or prevent further loss of BMD. Holcomb and Rothenberg (A-3) looked at 96 women taking alendronate to determine if a difference existed in the mean percent change in BMD among five different primary diagnosis classifications. Group 1 patients were diagnosed with rheumatoid arthritis (RA). Group 2 patients were a mixed collection of patients with diseases including lupus, Wegener’s granulomatosis and polyarteritis, and other vasculitic diseases (LUPUS). Group 3 patients had polymyalgia rheumatica or temporal arthritis (PMRTA). Group 4 patients had osteoarthritis (OA) and group 5 patients had osteoporosis (O) with no other rheumatic diseases identified in the medical record. Changes in BMD are shown in the following table. Discuss the Alendronate medication data in terms of variability. To determine if a difference…
(a) Using the information above, part of the ANOVA table is: Source of variation Sum of squares Region I error II Find the values of (round off to two decimal points) (1) I (11) II