A sample of 23 joint specimens of a particular type gave a sample mean proportional limit stress of 7.5 MPa and a sample standard deviation of 0.75 MPa. (a) Calculate the standard error. (Round your answer to four decimal places.) Calculate and interpret a 95% lower confidence bound for the true average proportional limit stress of all such joints. (Round your answer to two decimal places.)

A sample of 23 joint specimens of a particular type gave a sample mean proportional limit stress of 7.5 MPa and a sample standard deviation of 0.75 MPa. (a) Calculate the standard error. (Round your answer to four decimal places.) Calculate and interpret a 95% lower confidence bound for the true average proportional limit stress of all such joints. (Round your answer to two decimal places.)

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...

See similar textbooks

Similar questions

A nutritionist claims that the mean tuna consumption by a person is 3.4 pounds per year. A sample of 90 people shows that the mean tuna consumption by a person is 3.3 pounds per year. Assume the population standard deviation is 1.02 pounds. At α=0.03, can you reject the claim? (a) Identify the null hypothesis and alternative hypothesis. A. H0: μ=3.4 Ha: μ≠3.4 Your answer is correct. B. H0: μ>3.4 Ha: μ≤3.4 C. H0: μ≤3.3 Ha: μ>3.3 D. H0: μ≤3.4 Ha: μ>3.4 E. H0: μ>3.3 Ha: μ≤3.3 F. H0: μ≠3.3 Ha: μ=3.3 (b) Identify the standardized test statistic. z=negative 1.34−1.34 (Round to two decimal places as needed.)
You want to buy a washing machine, and a salesperson tells you that the mean repair costs for Model A and Model B are equal. You research the repair costs. The mean repair cost of 21 Model A washing machines is $215. Assume the population standard deviation is $19. The mean repair cost of 22 Model B washing machines is $221. Assume the population standard deviation is $20. At α=0.01, can you reject the salesperson's claim? Assume the samples are random and independent, and the populations are normally distributed.
Researchers conducted a study to determine whether magnets are effective in treating back pain. Pain was measured using the visual analog scale, and the results shown below are among the results obtained in the study. Higher scores correspond to greater pain levels. Assume that the two samples are independent simple random samples selected from normally distributed populations, and do not assume that the population standard deviations are equal. Complete parts (a) to (c) below. Reduction in Pain Level After Magnet Treatment (μ1): n=29, x=0.58, s=0.95 Reduction in Pain Level After Sham Treatment (μ2): n=29, x=0.48, s=1.56 Question content area bottom Part 1 a. Use a 0.05 significance level to test the claim that those treated with magnets have a greater mean reduction in pain than those given a sham treatment (similar to a placebo). What are the null and alternative hypotheses? A. H0: μ1≠μ2 H1: μ1<μ2 B. H0: μ1<μ2 H1:…
A researcher claims that the average wind speed in the desert is less than 18.3 kilometers per hour. A sample of 30 days has an average wind speed of 17 kilometers per hour. The standard deviation of the population is 2.8 kilometers per hour. At a = 0.05, is there enough evidence to reject the claim? a. If a hypothesis testing is to be undertaken, the z Test Value will be equal to:
The tensile strengths of two types of materials were investigated by collecting 16 samples of each material (totally 32 samples).The sample mean for material 1 was 423.08 (psi), and for material 2 was 424.7 (psi). The samplestandard deviation of the difference in tensile strengths was sD = 2.8 (psi). Is there sufficientevidence to conclude that two types of materials have the same tensile strength? Formulate andtest the appropriate null H0 and alternative hypotheses H1 to verify the claim at level α = 0.01
A nutritionist claims that the mean tuna consumption by a person is 3.3 pounds per year. A sample of 80 people shows that the mean tuna consumption by a person is 3.1 pounds per year. Assume the population standard deviation is 1.02 pounds. At a = 0.06, can you reject the claim? (a) Identify the null hypothesis and alternative hypothesis. OA. Ho: H>3.1 Ha: HS3.1 D. Ho: H=3.3 H₂:μ*3.3 OB. Ho: ≤3.3 H:H>3.3 OE. Ho: >3.3 Ha: 53.3 (b) Identify the standardized test statistic. z = (Round to two decimal places as needed.) OC. Ho: * 3.1 Ha: 3.1 OF. Ho: $3.1 H₂:μ>3.1
A nutritionist claims that the mean tuna consumption by a person is 3.9 pounds per year. A sample of 80 people shows that the mean tuna consumption by a person is 3.8 pounds per year. Assume the population standard deviation is 1.02 pounds. At a = 0.09, can you reject the claim? (a) Identify the null hypothesis and alternative hypothesis. O A. Ho: u>3.8 Ha: μs 3.8 O B. Ho: H#3.8 Ha: μ= 3.8 O C. Ho: Hs3.9 Hai H> 3.9 O D. Ho: H>3.9 O E. Ho: Hs3.8 Ha: H> 3.8 F. Ho: H=3.9 Ha:us3.9 Ha: H#3.9 (b) Identify the standardized test statistic. (Round to two decimal places as needed.)
The average price of a sample of 12 bottles of diet salad dressing taken from different stores is $1.43. The standard deviation is $0.09. The average price of a sample of 16 low-calorie frozen desserts is $1.03. The standard deviation is $0.10. At α = 0.05, is the price of salad dressings significantly higher than the price of frozen desserts?
The slant shear test is widely accepted for evaluating the bond of resinous repair materials to concrete; it utilizes cylinder specimens made of two identical halves bonded at 30°. An article reported that for 12 specimens prepared using wire-brushing, the sample mean shear strength (N/mm2) and sample standard deviation were 18.60 and 1.56, respectively, whereas for 12 hand-chiseled specimens, the corresponding values were 23.19 and 4.07. Does the true average strength appear to be different for the two methods of surface preparation? State and test the relevant hypotheses using a significance level of 0.05. (Use ?1 for wire-brushing and ?2 for hand-chiseling.) H0: ?1 − ?2 = 0Ha: ?1 − ?2 ≤ 0H0: ?1 − ?2 = 0Ha: ?1 − ?2 < 0 H0: ?1 − ?2 = 0Ha: ?1 − ?2 > 0H0: ?1 − ?2 = 0Ha: ?1 − ?2 ≠ 0 Calculate the test statistic and determine the P-value. (Round your test statistic to one decimal place and your P-value to three decimal places.) t = P-value = You may have computed…
Assume that the body mass index (BMI) of all American young women follows a Normal distribution with standard deviation σ = 7.5. How large a sample would be needed to estimate the mean BMI μ in this population to within ±1 with 95% confidence? (Enter your answer as a whole number.)
You want to buy a washing machine, and a salesperson tells you that the mean repair costs for Model A and Model B are equal. You research the repair costs. The mean repair cost of 24 Model A washing machines is $209. Assume the population standard deviation is $20. The mean repair cost of 27 Model B washing machines is $215. Assume the population standard deviation is $24. At α=0.01, can you reject the salesperson's claim? Assume the samples are random and independent, and the populations are normally distributed. Complete parts (a) through (e). (a) Identify the claim and state H0 and Ha. What is the claim? A. The mean repair costs for Model A and Model B are equal. B. The mean repair cost for Model A is greater than Model B. C. The mean repair costs for Model A and Model B are different. D. The mean repair cost for Model A is less than Model B. Let μ1 be the mean repair cost for Model A and let μ2 be the mean repair cost for Model B.…
Assume that the helium porosity (in percentage) of coal samples taken from any particular seam is normally distributed with true standard deviation 0.78. (c) How large a sample size is necessary if the width of the 95% interval is to be 0.31? (Round your answer up to the nearest whole number.) ? specimens (I have answers for a, b, and d I just need help with c, the answer is not 24.32)