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 Il ovens. A sample of 43 type I ovens has a mean repair cost of $70.15. with a standard deviation of $20.62. A sample of 57 type Il ovens has a mean repair cost of $65.36, with a standard deviation of $22.21. Conduct a hypothesis test of the technician's claim at the 0.05 level of significance. Let , be the true mean repair cost for type I ovens and ; be the true mean repair cost for type il ovens. Step 2 of 4: Compute the value of the test statistic. Round your answer to two decimal places. m Tables Keyрad Answer How to enter your answer Keyboard Shortcuts Previous Step Answers

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.)…

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…

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…

In a test of the effectiveness of garlic for lowering cholesterol, 49 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 0.6 and a standard deviation of 20.7. Use a 0.05 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? A. Ho: μ = 0 mg/dL H₁: μ> 0 mg/dL C. Ho: μ = 0 mg/dL H₁: μ#0 mg/dL Determine the test statistic. (Round to two decimal places as needed.) Determine the P-value. (Round to three decimal places as needed.) State the final conclusion that addresses the…

The distribution of professional baseball player salaries has a mean of $3.2 million. An analyst believes that the mean salary for teams on the East Coast is different. The analyst randomly selects 50 baseball players from teams on the East Coast and records their annual salaries. The mean salary for the players in the sample is $3.9 million with a standard deviation of $2.1 million. A significance test at an alpha level a = 0.05 of produces a P-value of 0.02. What is the corect interpretation of the P-value? O Assuming the true mean salary is $3.2 million, there is a 2% probability that the null hypothesis is true by chance alone. O Assuming the true mean salary is $3.2 million, there is a 2% probability of getting a sample mean of $3.9 million by chance alone. O Assuming the true mean salary is $3.2 million, there is a 2% probability of getting a sample mean at least as extreme as $3.9 million by chance alone. O Assuming the true mean salary is $3.2 million, there is a 98%…

In a test of the effectiveness of garlic for lowering cholesterol, 81 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 0.2 and a standard deviation of 17.2. Use a 0.05 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? Ο Α. Hρ: μ=0 mg/dL O B. Ho: µ=0 mg/dL H;: u#0 mg/dL H,: µ>0 mg/dL O C . H: μ=0 mg/dL O D. Ho: µ>0 mg/dL H;: µ<0 mg/dL H,:µ<0 mg/dL Determine the test statistic. (Round to two decimal places as needed.) Determine the P-value, (Round to three decimal…

A food distribution company claims that a restaurant chain receives, on average, 26 pounds of fresh vegetables on a daily basis. The standard deviation of these shipments is known to be 4.4 pounds. The district manager of the restaurant chain decides to randomly sample 35 shipments from the company and finds a mean weight of 24.7 pounds. Test at a 3% level of significance to determine whether or not the food distribution company sends less than 26 pounds of fresh vegetables. a. Check the TWO requirements that are satisfied. The Central Limit Theorem applies. The a distribution is normal since n > 30. The a distribution is normal since the x distribution is normal. The p distribution is normal since np > 5 and nq > 5.

The distribution of professional baseball player salaries has a mean of $3.2 million. An analyst believes that the mean salary for teams on the East Coast is different. The analyst randomly selects 50 baseball players from teams on the East Coast and records their annual salaries. The mean salary for the players in the sample is $3.9 million with a standard deviation of $2.1 million. A significance test at an alpha level a = 0.05 of produces a P-value of 0.02. What is the correct interpretation of the P-value? Assuming the true mean salary is $3.2 million, there is a 2% probability that the null hypothesis is true by chance alone. Assuming the true mean salary is $3.2 million, there is a 2% probability of getting a sample mean of $3.9 million by chance alone. Assuming the true mean salary is $3.2 million, there is a 2% probability of getting a sample mean at least as extreme as $3.9 million by chance alone. Assuming the true mean salary is $3.2 million, there is a 98% probability that…

Community college instructors' salaries in one state are very low, so low that educators in that state regularly complain about their compensation. The national mean is $57,636$⁢57,636, but instructors from Mississippi claim that the mean in their state is significantly lower. They survey a simple random sample of 3737 colleges in the state and calculate a mean salary of $52,534$⁢52,534 with a standard deviation of $15,791$⁢15,791. Test the instructors' claim at the 0.050.05 level of significance.   Step 3 of 3 :  Draw a conclusion and interpret the decision.