Home / Questions / Consider the accompanying data on flexural strength MPa for concrete beams of a certain type
Consider the accompanying data on flexural strength (MPa) for concrete beams of a certain type.
5.0 | 7.2 | 7.3 | 6.3 | 8.1 | 6.8 | 7.0 | 7.0 | 6.8 | 6.5 | 7.0 | 6.3 | 7.9 | 9.0 |
8.1 | 8.7 | 7.8 | 9.7 | 7.4 | 7.7 | 9.7 | 8.0 | 7.7 | 11.6 | 11.3 | 11.8 | 10.7 |
The data below give accompanying strength observations for cylinders.
6.7 | 5.8 | 7.8 | 7.1 | 7.2 | 9.2 | 6.6 | 8.3 | 7.0 | 8.0 |
7.8 | 8.1 | 7.4 | 8.5 | 8.9 | 9.8 | 9.7 | 14.1 | 12.6 | 11.6 |
Prior to obtaining data, denote the beam strengths by X_{1}, . . . , X_{m} and the cylinder strengths by Y_{1}, . . . , Y_{n}. Suppose that the X_{i}'s constitute a random sample from a distribution with mean Î¼_{1} and standard deviation Ïƒ_{1} and that the Y_{i}'s form a random sample (independent of the X_{i}'s) from another distribution with mean Î¼_{2} and standard deviation Ïƒ_{2}.
(a) Use rules of expected value to show that
X âˆ’ Y
is an unbiased estimator of Î¼_{1} âˆ’ Î¼_{2}.E(X âˆ’ Y) =
Answer: E(X âˆ’ Y) = E(X) âˆ’ E(Y) = Î¼_{1} âˆ’ Î¼_{2 **THIS IS CORRECT**}
Calculate the estimate for the given data. (Round your answer to three decimal places.)
MPa
_______________________???
(b) Use rules of variance to obtain an expression for the variance and standard deviation (standard error) of the estimator in part (a).
Compute the estimated standard error. (Round your answer to three decimal places.)
_____________________ MPa
(c) Calculate a point estimate of the ratio Ïƒ_{1}/Ïƒ_{2} of the two standard deviations. (Round your answer to three decimal places.)
______________________???
(d) Suppose a single beam and a single cylinder are randomly selected. Calculate a point estimate of the variance of the difference X âˆ’ Y between beam strength and cylinder strength. (Round your answer to two decimal places.)
_________________MPa^{2}
Apr 25 2020 View more View Less
The Older Worker Benefit Protection Act (OWBPA) sets forth some very specific conditions that must be met when older workersa.move from full-time to part-time status.b.ar...
Dec 13 2019Computing second-year depreciation and accumulated depreciation At the beginning of 2016, Logan Service purchased a used airplane at a cost of $46,000,000. Logan Service ...
Apr 21 2020Verbal ability of delinquents. Over the past 20 years, the Journal of Abnormal Psychology has published numerous studies on the relationship between juvenile delinquency ...
Aug 06 2020The expansion of the definition of marketing to include non-business activities adds which one of these examples to the field of marketing? [A]Proctor and Gamble selling...
Dec 14 2017Which of the following capital is taken up by the general public? (A) Issued capital (B) Subscribed capital (C) Authorized capital (D) Reserve capital
Apr 11 2018b. What is the cost of external common equity for the firm?c. What is the cost of internal common equity?d. What is the cost of preferred stock?e. What is the after-tax c...
May 29 2020Which of the following plantwide plans incorporates the ideas of employees, union leaders, and top managers to generate cost-saving ideas?A) ImproshareB) Rucker planC) Sc...
Dec 12 2019A few years ago, Spider Web, Inc. issued bonds with a 11.42 percent annual coupon rate, paid semiannually. The bonds have a par value of $1,000, a current price of $742, ...
Aug 19 2020In the 20th and 21st century, consumer protection laws haveproliferated. Do you think that these laws have become overlyburdensome for businesses to comply with?Please id...
May 25 2021EXERCISE 15–1 Common-Size Income Statement [LO1]A comparative income statement is given below for Ryder Company:Sales . . . . . . . . . . . . . . . . . . . . . . . . . ....
Jun 28 2020