4) The strength limit of a specific type of a cable is random variable with meanvalue of 1500 kg and standard deviation 175 kg. The factory that manufacturesthis type of cables claims that they improved the materials that they used andthe new resistance limit of the cable has increased. We randomly chose asample of 50 cables and the mean strength limit was 1570 kg. If the strengthlimit in the specific type of cable is normally distributed with a significancelevel of 0.05, can we state that the claim of the manufacture factory is true?Justify your answer.

The question is about hypo. testing for a popl. mean Given : Popl. mean strength limit of specific…

Answered: 4) The strength limit of a specific…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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The breaking strengths of cables produced by a certain manufacturer have historically had a mean of 1775 pounds and a standard deviation of 70 pounds. The company believes that, due to an improvement in the manufacturing process, the mean breaking strength, u, of the cables is now greater than 1775 pounds. To see if this is the case, 14 newly manufactured cables are randomly chosen and tested, and their mean breaking strength is found to be 1812 pounds. Assume that the population is normally distributed. Can we support, at the 0.10 level of significance, the claim that the population mean breaking strength of the newly- manufactured cables is greater than 1775 pounds? Assume that the population standard deviation has not changed. Perform a one-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.) (a) State the null hypothesis H, and the…
Paint used to paint lines on roads must reflect enough light to be clearly visible at night. Researchers have 2 new types of paints they want to test paint type A and paint type B. For each paint type, they tested if there was statistical evidence the average reflectometer reading is greater than 35. To test each type of paint, they used 15 paint samples. Further, suppose the standard deviation is the same for both types of paints. The sample mean for paint type A was 39 and the sample mean for paint type B was 41.5. For both statistical tests, the significance level is set to .05.Which of the following is true? If they fail to reject the null hypothesis for paint type A we can conclude there is statistical evidence the average reflectometer for type A paint is 35. The p-value for the type B paint test is smaller. They rejected the null hypothesis for both paint types. Exactly two of the statements above are true. None are true.
The breaking strengths of cables produced by a certain manufacturer have historically had a mean of 1775 pounds and a standard deviation of 60 pounds. The company believes that, due to an improvement in the manufacturing process, the mean breaking strength, μ, of the cables is now greater than 1775 pounds. To see if this is the case, 90 newly manufactured cables are randomly chosen and tested, and their mean breaking strength is found to be 1788 pounds. Can we support, at the 0.05level of significance, the claim that the population mean breaking strength of the newly-manufactured cables is greater than 1775 pounds? Assume that the population standard deviation has not changed. Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places, and round your responses as specified below. a. State the null hypothesis H0 and the alternative hyposthesis H1. b. Find the value of the test statistic. c. Find the p-value. d. Can we…
At the alpha = 0.01 level , what is the correct conclusion for this test? The daily temperatures in fall and winter months in Virginia have a mean of 62F. A meteorologist in southwest Virginia believes the mean temperature is colder in this area. The meteorologist takes a random sample of 30 daily temperatures from the fall and winter months over the last five years in southwest Virginia. The mean temperature for the sample is 59 degrees * F with a standard deviation of 6.21 degrees * F The meteorologist conducts a one -sample t-test for and calculates a P value of 0.007. The meteorologist should reject the null hypothesis since 0.007 < 0.01 . There is convincing evidence that the mean temperature in fall and winter months in southwest Virginia is less than 62 F. The meteorologist should reject the null hypothesis since 0.007 < 0.01 . There is not convincing evidence that the mean temperature in fall and winter months in southwest Virginia is less than 62 F. The meteorologist…
Fran is training for her first marathon, and she wants to know if there is a significant difference between the mean number of miles run each week by group runners and individual runners who are training for marathons. She interviews 42 randomly selected people who train in groups and finds that they run a mean of 47.1 miles per week. Assume that the population standard deviation for group runners is known to be 4.4 miles per week. She also interviews a random sample of 47 people who train on their own and finds that they run a mean of 48.5 miles per week. Assume that the population standard deviation for people who run by themselves is 1.8 miles per week. Test the claim at the 0.01 level of significance. Let group runners training for marathons be Population 1 and let individual runners training for marathons be Population 2. Step 2 of 3 : Compute the value of the test statistic. Round your answer to two decimal places.
Bone mineral density (BMD) is a measure of bone strength. Studies show that BMD declines after age 45. The impact of exercise may increase BMD. A random sample of 59 women between the ages of 41 and 45 with no major health problems were studied. The women were classified into one of two groups based upon their level of exercise activity: walking women and sedentary women. The 39 women who walked regularly had a mean BMD of 5.96 with a standard deviation of 1.22. The 20 women who are sedentary had a mean BMD of 4.41 with a standard deviation of 1.02. Which of the following inference procedures could be used to estimate the difference in the mean BMD for these two types of women
A researcher is studying how much electricity (in kilowatt hours) people from two different cities use in their homes. Random samples of 13 days from Nashville (Group 1) and 14 days from Cincinnati (Group 2) are shown below. Test the claim that the mean number of kilowatt hours in Nashville is less than the mean number of kilowatt hours in Cincinnati. Use a significance level of a = 0.10. Assume the populations are approximately normally distributed with unequal variances. Round answers to 4 decimal places. Nashville Cincinnati 902.6 892.9 904.9 897.5 905.2 904.1 911.4 883.9 898.7 887.7 889.7 907.2 899.1 Ho: M₁ What are the correct hypotheses? Note this may view better in full screen mode. Select the correct symbols for each of the 6 spaces. 921.2 931.1 908.3 939.6 898 934.6 906.6 921.2 907.5 902.4 883.6 893.1 Test Statistic = 941.4 923.6 p-value = H₁: M₁ Based on the hypotheses, find the following: H₁₂ H₂ Or
The breaking strengths of cables produced by a certain manufacturer have historically had a mean of 1800 pounds and a standard deviation of 90 pounds. The company believes that, due to an improvement in the manufacturing process, the mean breaking strength, μ, of the cables is now greater than 1800 pounds. To see if this is the case, 100 newly manufactured cables are randomly chosen and tested, and their mean breaking strength is found to be 1818 pounds. Can we support, at the 0.05 level of significance, the claim that the population mean breaking strength of the newly- manufactured cables is greater than 1800 pounds? Assume that the population standard deviation has not changed. Perform a one-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.) (a) State the null hypothesis Ho and the alternative hypothesis H₁. H :O 1 (b) Determine the…
The breaking force of the cables produced by a manufacturer is 1800 lbs (lb) and the standard deviation is 100 lbs. It is claimed that the breaking force can be increased with a new technique in the manufacturing process. To test this claim, a sample of 50 wires is taken and tested. The average breaking force of the samples is found as 1850 lb. Can we support this claim at the 0.01 significance level?
A simple random sample of 43 men from a normally distributed population results in a standard deviation of 11.1 beats per minute. The normal range of pulse rates of adults is typically given as 60 to 100 beats per minute. If the range rule of thumb is applied to that normal range, the result is a standard deviation of 10 beats per minute. Use the sample results with a 0.10 significance level to test the claim that pulse rates of men have a standard deviation equal to 10 beats per minute. Complete parts (a) through (d) below.
According to an article in Good Housekeeping, a 128-lb woman who walks for 30 minutes four times a week at a steady, four-mi/hr pace can lose up to 10 lbs over a span of a year. Suppose 35 women with weights between 125 and 130lb perform the four walks per week for a year and at the end of the year the average weight loss for the 35 was 9.1 lbs. If the sample standard deviation is 5, calculate the value of the test statistic and find the p-value of the hypothesis test of Ho:µ =10 vs H1:µ≠10.
A researcher decides to measure anxiety in group of bullies and a group of bystanders using a 23-item, 3 point anxiety scale. Assume scores on the anxiety scales are normally distributed and the variance among the group of bullies and bystanders are the same. A group of 30 bullies scores an average of 21.5 with a sample standard deviation of 10 on the anxiety scale. A group of 27 bystanders scored an average of 25.8 with a sample standard deviation of 8 on the anxiety scale. You do not have any presupposed assumptions whether bullies or bystanders will be more anxious so you formulate the null and alternative hypothesis based on that.

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