The tensile strength of steel rods produced by a manufacturer has a mean of 31MPa and the standard deviation of 1.5MPa. By a new technique in the manufacturing process , it is claimed that the tensile strength can be improved. To test this claim, a sample of 48 steel bars is tested and it is found that the mean tensile strength is 31.5 can we support the claim at 0.05 level of significance?
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The tensile strength of steel rods produced by a manufacturer has a
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- The gasoline consumption projected for a car model is 13 km / l. After the launch of the vehicle, a specialized magazine carried out a test that showed 1300 cars, an average consumption of 12.3 km / l. The manufacturer claims that the standard deviation of consumption is 0.5 km / l. test the hypothesis that consumption is at least 13km / l.The tensile strength of steel bars produced by a manufacturer has a mean 30 MPa and the [10] standard deviation of 1.5MPa. By a new technique in the manufacturing process, it is claimed that the tensile strength can be improved. To test this claim, a sample of 50 steel bars is tested and it is found that the mean tensile strength is 30.5MPa. Can we support the claim at 0.01 level of significance?a) Soil has been improved to increase the strength of a ground. The average compressive strength of 61 samples before treatment is 45 kg / cm2 and the standard deviation is 6.75 kg / cm2; The average compressive strength of 56 samples after the improvement is 52.5 kg / cm2 and the standard deviation is 8 kg / cm2. Determine whether the improvement application changes the standard deviation of the soil strength or not at the 5% significance level .b) Find the confidence intervals at the 7% significance level of the mean compressive strength of the sample after improvement?
- The time it takes for a compact fluorescent bulb to reach full brightness is normally distributed with mean 29.9 seconds and standard deviation 4.1 seconds. Find and interpret the z-score for x = 26.4.Suppose that a Normal model describes furl economy (mile per gallon) for automobile and that a Saturn has a standardized score ( z score) of +2.2. This meatn taht Satturn.... gets 2.2 miler sper gallon. get 2.2 times the gas mileage of the avereage car. get 2.2 mpg more than the average car. have a standard deviation of 2.2 mpg achieve fuel eceonomy that is 2.2 standard deviations better thean the average car.A laboratory claims that the mean sodium level, μ , of a healthy adult is 141 mEq per liter of blood. To test this claim, a random sample of 80 adult patients is evaluated. The mean sodium level for the sample is 142 mEq per liter of blood. It is known that the population standard deviation of adult sodium levels is 11 mEq. Can we conclude, at the 0.05 level of significance, that the population mean adult sodium level differs from that claimed by the laboratory? Perform a two-tailed test. Then fill in the table below. Carry your intermediate computations to at least three decimal places, and round your responses as specified in the table. The null hypothesis: H0: The alternative hypothesis: H1: The type of test statistic: (Choose one)ZtChi squareF The value of the test statistic:(Round to at least three decimal places.) The two critical values at the 0.05 level of significance:(Round to at least…
- A laboratory claims that the mean sodium level, u, of a healthy adult is 143 mEq per liter of blood. To test this claim, a random sample of 50 adult patients is evaluated. The mean sodium level for the sample is 140 mEq per liter of blood. It is known that the population standard deviation of adult sodium levels is 10 mEq. Can we conclude, at the 0.1 level of significance, that the population mean adult sodium level differs from that claimed by the laboratory? Perform a two-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places, and round your responses as specified below. (If necessary, consult a list of formulas.)It takes an average of 14.5 minutes for blood to begin clotting after an injury. An EMT wants to see if the average will increase if the patient is immediately told the truth about the injury. The EMT randomly selected 65 injured patients to immediately tell the truth about the injury and noticed that they averaged 15.4 minutes for their blood to begin clotting after their injury. Their standard deviation was 3.05 minutes. What can be concluded at the the αα = 0.05 level of significance? For this study, we should use The null and alternative hypotheses would be: H0:H0: H1:H1: The test statistic = (please show your answer to 3 decimal places.) The p-value = (Please show your answer to 4 decimal places.) The p-value is αα Based on this, we should the null hypothesis. Thus, the final conclusion is that ... The data suggest the populaton mean is significantly greater than 14.5 at αα = 0.05, so there is statistically significant…It takes an average of 10.8 minutes for blood to begin clotting after an injury. An EMT wants to see if the average will increase if the patient is immediately told the truth about the injury. The EMT randomly selected 46 injured patients to immediately tell the truth about the injury and noticed that they averaged 11.7 minutes for their blood to begin clotting after their injury. Their standard deviation was 2.98 minutes. What can be concluded at the the αα = 0.05 level of significance? The null and alternative hypotheses would be: Please provide number H0:H0: mean =Correct __?__ H1:H1: mean > Correct_ __?__ The test statistic t = __?__ (please show your answer to 3 decimal places.) The p-value = __?__ (Please show your answer to 4 decimal places.)
- The average local cell phone call length was reported to be 2.27 minutes. A random sample of 10phone calls showed an average of 2.98 minutes in length with a standard deviation of 0.98 minute. At alpha= 0.01can it be concluded that the average differs from the population average?The manufacturer of a particular brand of tires claims they average at least 50,000 miles before needing to be replaced. From past studies of this tire, it is known that the population standard deviation is 8,000 miles. A survey of tire owners was conducted. From the 23 tires surveyed, the mean lifespan was 43500 miles. Using alpha = 0.05, can we prove that the data in inconsistent with the manufacturers claim? We should use a t v test. What are the correct hypotheses? Ho: Select an answer v| ? v H Select an answer | ? v Based on the hypotheses, find the following: Test Statistic= p-value- The correct decision is to Select an answer The correct conclusion would be: Select an answer Question Help: M Message İnstructor Submit Question MacBook Pro FR.I END.S DD F8 F9 F10 F11 F12 F7 & 8 9 deleteDuring the busy season, it is important for the shipping manager at ShipMundo to be able to estimate the time it takes the loading crew to load a truck. The shipping manager has found that she can model the load times using a normal distribution with a mean of 152 minutes and a standard deviation of 15 minutes. Use this table or the ALEKS calculator to find the percentage of load times between 116 minutes and 149 minutes according to the model. For your intermediate computations, use four or more decimal places. Give your final answer to two decimal places (for example 98.23%).
