Consider the accompanying data on flexural strength (MPa) for concrete beams of a certain type. 5.9 7.2 7.3 6.3 8.1 6.8 7.0 7.2 6.8 6.5 7.0 6.3 7.9 9.0 8.4 8.7 7.8 9.7 7.4 7.7 9.7 8.1 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 8.1 7.0 8.1 7.4 8.5 8.9 9.8 9.7 14.1 12.6 11.4 Prior to obtaining data, denote the beam strengths by X₁X and the cylinder strengths by Y. Y Suppose that the X's constitute a random sample from a distribution with mean and standard deviation and that the Y's form a random sample (independent of the X's) from another distribution with mean and standard deviation d (a) Use rules of expected value to show that X-F is an unbiased estimator of ₂-2- E(X)=√E(X)=E(V)-#₁ - #2 • ECR-5)- 800) - 80-1₂-₂ 0-5-0-0. 0 € - ³) = ² = 4₂-₂ EUX-(C)- () -- O ○ £₁² - ³) - (EU) - ²(ñ)² = P₁-P2 Calculate the estimate for the given data. (Round your answer to three decimal places.) (b) Use rules of variance to obtain an expression for the variance and standard deviation (standard error) of the estimator in part (a). vox-5-v+v -07+07 8-9-√VX-5 "1 Compute the estimated standard error. (Round your answer to three decimal places.) (c) Calculate a point estimate of the ratio d/d 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-Y between beam strength and cylinder strength. (Round your answer to two decimal places.) MP₂²

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...
icon
Related questions
Question
Consider the accompanying data on flexural strength (MPa) for concrete beams of a certain type.
7.0 7.2 6.8 6.5 7.0 6.3 7.9 9.0
9.7 8.1 7.7 11.6 11.3 11.8 10.7
observations for cylinders.
5.9 7.2 7.3 6.3 8.1 6.8
8.4 8.7 7.8 9.7 7.4 7.7
The data below give accompanying strength
6.7 5.8 7.8 7.1 7.2 9.2 6.6 8.3 7.0 8.1
7.0 8.1 7.4 8.5 8.9 9.8 9.7 14.1 12.6 11.4
Prior to obtaining data, denote the beam strengths by X₁,..., Xm and the cylinder strengths by Y₁,..., Y. Suppose that the Xi's constitute a random sample from a distribution with mean ₁ and standard deviation 0₁ and that the Y's form a random sample (independent of the X;'s) from another distribution with mean ₂ and standard
deviation ₂.
(a) Use rules of expected value to show that X - Y is an unbiased estimator of μ₁ - μ₂.
O E(X)=√E(X) - E(Y) = μ₁ - H₂
ⒸE(XY) = E(X) - E(X) = 14₁ 14₂
O E(X-= E(X) - E(X) = 11 - 12
nm
E(X - Y = nm(E(X) - E()) = μ₁ −
44₂
| E(X) = (E(X) - E(M)² =
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).
v(x) = V(X) + (5)
= 0x² + 0x²
01
= khi khô
ox-Y = √V(x - y)
n1
0₂²
Compute the estimated standard error. (Round your answer to three decimal places.)
MPa
(c) Calculate a point estimate of the ratio 0₁/02 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 - Y between beam strength and cylinder strength. (Round your answer to two decimal places.)
MPa²
Transcribed Image Text:Consider the accompanying data on flexural strength (MPa) for concrete beams of a certain type. 7.0 7.2 6.8 6.5 7.0 6.3 7.9 9.0 9.7 8.1 7.7 11.6 11.3 11.8 10.7 observations for cylinders. 5.9 7.2 7.3 6.3 8.1 6.8 8.4 8.7 7.8 9.7 7.4 7.7 The data below give accompanying strength 6.7 5.8 7.8 7.1 7.2 9.2 6.6 8.3 7.0 8.1 7.0 8.1 7.4 8.5 8.9 9.8 9.7 14.1 12.6 11.4 Prior to obtaining data, denote the beam strengths by X₁,..., Xm and the cylinder strengths by Y₁,..., Y. Suppose that the Xi's constitute a random sample from a distribution with mean ₁ and standard deviation 0₁ and that the Y's form a random sample (independent of the X;'s) from another distribution with mean ₂ and standard deviation ₂. (a) Use rules of expected value to show that X - Y is an unbiased estimator of μ₁ - μ₂. O E(X)=√E(X) - E(Y) = μ₁ - H₂ ⒸE(XY) = E(X) - E(X) = 14₁ 14₂ O E(X-= E(X) - E(X) = 11 - 12 nm E(X - Y = nm(E(X) - E()) = μ₁ − 44₂ | E(X) = (E(X) - E(M)² = 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). v(x) = V(X) + (5) = 0x² + 0x² 01 = khi khô ox-Y = √V(x - y) n1 0₂² Compute the estimated standard error. (Round your answer to three decimal places.) MPa (c) Calculate a point estimate of the ratio 0₁/02 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 - Y between beam strength and cylinder strength. (Round your answer to two decimal places.) MPa²
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 4 steps

Blurred answer
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
A First Course in Probability (10th Edition)
A First Course in Probability (10th Edition)
Probability
ISBN:
9780134753119
Author:
Sheldon Ross
Publisher:
PEARSON
A First Course in Probability
A First Course in Probability
Probability
ISBN:
9780321794772
Author:
Sheldon Ross
Publisher:
PEARSON