Register

3. A civil engineer is analyzing the compressive strength of concrete. Compressive strength is normally distributed with σ2 = 1000 (psi)2 . A random sample of 12 specimens has a…

3. A civil engineer is analyzing the compressive strength of concrete. Compressive strength is normally distributed with σ2 = 1000 (psi)2 . A random sample of 12 specimens has a…
asked 216k views
3 votes
3. A civil engineer is analyzing the compressive strength of concrete. Compressive strength is normally distributed with σ2 = 1000 (psi)2 . A random sample of 12 specimens has a mean compressive strength of 3250 psi. (a) Construct a 95% two-sided confidence interval on the mean compressive strength. (b) Suppose it is desired to estimate the mean compressive strength with an error that is less than 15 psi at 99% confidence. What is the sample size required?

asked
User Nihat
by
7.8k points

1 Answer

4 votes

Answer: a) 3232.1077 < u < 3267.8923

b) 3226.448 <u< 3273.552

Step-by-step explanation:

3. A civil engineer is analyzing the compressive strength of concrete. Compressive-example-1
answered
User Gray Adams
by
9.2k points
← Prev Question Next Question →

Related questions

Ask a Question
Welcome to Qamnty — a place to ask, share, and grow together. Join our community and get real answers from real people.

Categories

Other Questions

A piston-cylinder device fitted with stops in the cylinder walls contains 2.1 kg of water initially at 150 kPa and 30 °C. Heat is transferred to the system until the final temperature reaches 250 °C. The
A water towers lowest point is 405 ft and the main line is 6 feet below the ground. The ground elevation is at 276 ft. The main line travels 2.9 miles. The pipe will travel through the following flanged
An activated sludge plant is being designed to handle a feed rate of 0.438 m3 /sec. The influent BOD concentration is 150 mg/L and the cell concentration (MLVSS) is 2,200 mg/L. If you wish to operate the
Link Copied!