Pearson eText for Materials for Civil and Construction Engineers -- Instant Access (Pearson+)
Pearson eText for Materials for Civil and Construction Engineers -- Instant Access (Pearson+)
4th Edition
ISBN: 9780137505586
Author: Michael Mamlouk, John Zaniewski
Publisher: PEARSON+
bartleby

Videos

Textbook Question
Book Icon
Chapter 1, Problem 1.45QP

A contractor claims that the mean compressive strength for a concrete mix is 32.4 MPa and that it has a standard deviation of 2.8 MPa. If you break 16 cylinders and obtain a mean compressive strength of 30.3 MPa, would you believe the contractor’s claim? Why? (Hint: Use statistical t-test.)

Blurred answer
Students have asked these similar questions
A contractor claims that the mean compressive strength for a concrete mix is 5,000 psi and that it has a standard deviation of 400 psi. If you break 20 cylinders and obtain a mean compressive strength of 4,800 psi, would you believe the contractor’s claim? Why? (Hint: Use statistical t-test.)
1.46: A contractor claims that the mean compressive strength for a concrete mix is 5000 psi (μ) and that it has a standard deviation of 400 psi (σ). If you break 20 cylinders (N) and obtain a mean compressive strength of 4,800 psi (m), would you believe the contractor’s claim? Why? (Hint; Use statistical t-test.) Next, what is the maximum number of breaks (N) that could be performed that WOULD make you believe the contractor’s claim? Assume that the results wouldn’t change, i.e. σ = 400 psi and m = 4,800 psi. Recall that the equation to find the lower bound of a one sided distribution is LB = μ - (tσ)* σ/(N^0.5) Because the sample size is relatively small, use the ‘student t test’ to represent the normal distribution. You should have at least 95% confidence in the results. That means that α = 0.05. Keep in mind that this is a one tailed distribution, since we only care about the lower bound (i.e. meaning that we are only concerned about concrete that doesn’t meet our minimum strength…
A contractor claims that the mean compressive strength for a concrete mix is 4,830 psi and that it has a standard deviation of 430 psi obtained from testing 22 specimens. If you break 20 cylinders and obtain a mean compressive strength of 4,450 psi and a standard deviation of 480 psi, would you believe the contractor’s claim? Why? (With a 95% confidence interval)

Chapter 1 Solutions

Pearson eText for Materials for Civil and Construction Engineers -- Instant Access (Pearson+)

Ch. 1 - The rectangular block shown in Figure P1.11 is...Ch. 1 - The rectangular metal block shown in Figure P1.11...Ch. 1 - A cylindrical rod with a length of 380 mm and a...Ch. 1 - A cylindrical rod with a radius of 0.3 in. and a...Ch. 1 - A cylindrical rod with a diameter of 15.24 mm and...Ch. 1 - The stressstrain relationship shown in Figure...Ch. 1 - A tension test performed on a metal specimen to...Ch. 1 - An alloy has a yield strength of 41 ksi, a tensile...Ch. 1 - Prob. 1.21QPCh. 1 - Figure P1.22 shows (i) elasticperfectly plastic...Ch. 1 - An elastoplastic material with strain hardening...Ch. 1 - A brace alloy rod having a cross sectional area of...Ch. 1 - A brass alloy rod having a cross sectional area of...Ch. 1 - A copper rod with a diameter of 19 mm, modulus of...Ch. 1 - A copper rod with a diameter of 0.5 in., modulus...Ch. 1 - Define the following material behavior and provide...Ch. 1 - An asphalt concrete cylindrical specimen with a...Ch. 1 - What are the differences between modulus of...Ch. 1 - Prob. 1.33QPCh. 1 - A metal rod having a diameter of 10 mm is...Ch. 1 - What is the factor of safety? On what basis is its...Ch. 1 - Prob. 1.36QPCh. 1 - Prob. 1.37QPCh. 1 - A steel rod, which is free to move, has a length...Ch. 1 - In Problem 1.38, if the rod is snugly fitted...Ch. 1 - A 4-m-long steel plate with a rectangular cross...Ch. 1 - Estimate the tensile strength required to prevent...Ch. 1 - Prob. 1.42QPCh. 1 - Briefly discuss the variability of construction...Ch. 1 - In order to evaluate the properties of a material,...Ch. 1 - A contractor claims that the mean compressive...Ch. 1 - A contractor claims that the mean compressive...Ch. 1 - Prob. 1.47QPCh. 1 - Prob. 1.48QPCh. 1 - Prob. 1.49QPCh. 1 - Briefly discuss the concept behind each of the...Ch. 1 - Referring to the dial gauge shown in Figure P1.51,...Ch. 1 - Repeat Problem 1.51 using the dial gauge shown in...Ch. 1 - Measurements should be reported to the nearest...Ch. 1 - During calibration of an LVDT, the data shown in...Ch. 1 - During calibration of an LVDT, the data shown in...
Knowledge Booster
Background pattern image
Civil Engineering
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, civil-engineering and related others by exploring similar questions and additional content below.
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Structural Analysis
Civil Engineering
ISBN:9781337630931
Author:KASSIMALI, Aslam.
Publisher:Cengage,
Text book image
Structural Analysis (10th Edition)
Civil Engineering
ISBN:9780134610672
Author:Russell C. Hibbeler
Publisher:PEARSON
Text book image
Principles of Foundation Engineering (MindTap Cou...
Civil Engineering
ISBN:9781337705028
Author:Braja M. Das, Nagaratnam Sivakugan
Publisher:Cengage Learning
Text book image
Fundamentals of Structural Analysis
Civil Engineering
ISBN:9780073398006
Author:Kenneth M. Leet Emeritus, Chia-Ming Uang, Joel Lanning
Publisher:McGraw-Hill Education
Text book image
Sustainable Energy
Civil Engineering
ISBN:9781337551663
Author:DUNLAP, Richard A.
Publisher:Cengage,
Text book image
Traffic and Highway Engineering
Civil Engineering
ISBN:9781305156241
Author:Garber, Nicholas J.
Publisher:Cengage Learning
Concrete Slab Calculations 006; Author: Jerry Howard;https://www.youtube.com/watch?v=R19jILyBxio;License: Standard Youtube License