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The design of a concrete mix requires 1173 kg/m3
of gravel in dry condition, 582 kg/m³ of sand in dry condition, and 157 kg/m³of free water. The gravel available at the job site has a moisture content of 0.8% and absorption of 1.5%, and the available sand has a moisture content of 1.1% and absorption of 1.3%. What are the masses of gravel, sand, and water per cubic meter that should be used at the job site?
12. Could a straight-line demand curve ever have the same elasticity on all its points?
What is your recommendation for the maximum size of coarse aggregate for the following situation? A continuously reinforced concrete pavement cross section contains a layer of No.6 reinforcing bars at 6-inch centers, such that the steel is just above mid-depth of a 10-inchthick slab. Cover over the top of the steel is therefore about 4 inches.
A project specifies a concrete strength of at least 3000 psi. Materials engineers will design
the mix for a strength higher than that. Calculate the required average compressive strength of
the mix design if the standard deviation is s = 350 psi. Estimate the modulus of elasticity of the
concrete at the required average compressive strength.
A project specifies a concrete strength of at least 3000 psi. Materials engineers will design
the mix for a strength higher than that. Calculate the required average compressive strength of
the mix design if the standard deviation is s = 350 psi. Estimate the modulus of elasticity of the
concrete at the required average compressive strength.
The weights of male students are normally distributed with a mean of 150 lbs. and a standard deviation of 25 lbs. What is the probability that 25 randomly selected make students will have a mean weight of more than 155 lbs?
The design engineer specifies a concrete strength of 5500 psi. Determine the required
average compressive strength for:
a. A new plant where s is unknows
b. A plant where s = 500 psi for 22 test results
c. A plant with extensive history of producing concrete with s = 400 psi
d. A plant with extensive history of producing concrete with s = 600 psi
A test taken by five people has a maximum score of 100. Their scores are 78, 65, 86, 91 and 68.
1. Compute for the mean of the population.
2. Compute for the variance of the population.
3. List all the possible samples of size 3 that can be drawn from the population and compute for the mean of each sample. Use SRSWOR method.
4. Construct the probability distribution of the sample means.
5. Compute the mean of the sampling distribution of the sample means.
6. Compute the variance of the sampling distribution of the sample means
If the pressure in container A in Fig. P2.38 is 150 kPa,
compute the pressure in container B.
The probabilities that a traffic inspector will discover violations of the Traffic Code in Davao City are given in the following table.
Number of Violations (X)
Probability P(X)
0.41
1
2
3
0.22
0.17
4
5
0.13
0.05
0.02
a. Solve for the mean and variance. b. Interpret the mean and the variance of the problem.
#340153 on Dec 2023