The tensile strength of stainless steel produced by a plant has been stable for a long...
The tensile strength of stainless steel produced by a plant has been stable for a long time with a mean of 72 kg/mm2 and a standard deviation of 2.15. A machine was recently adjusted and a sample of 50 items were taken to determine if the mean tensile strength has changed. The mean of this sample is 74.28. Assume that the standard deviation did not change because of the adjustment to the machine. Find a 95% confidence interval for the mean of tensile strength after the machine was adjusted. Does this data suggest that the tensile strength was changed after the adjustment?
Homework Answers
We need to construct the 95% confidence interval for the population mean μ. The following information is provided:
| Sample Mean | 74.28 |
| Population Standard Deviation | 2.15 |
| Sample Size | 50 |
The critical value for α=0.05 is z_c = 1.96 . The corresponding confidence interval is computed as shown below:
CI = (73.684, 74.876)
Since the interval does not contain 72 and even the lower limit is more than 72. hence the tensile strength has improved
Add Answer to:
The tensile strength of stainless steel produced by a plant has
been stable for a long...
Pr。Ыет 12. An engineer who is studying the tensile strength of a steel alloy intended for use in golf club shafts knows that tensile strength is approximately normally distributed. A random sample o...
Pr。Ыет 12. An engineer who is studying the tensile strength of a steel alloy intended for use in golf club shafts knows that tensile strength is approximately normally distributed. A random sample of 12 specimens has a mean tensile strength of 3250 psi and a sample standard deviation of 8-60 psi. a) Test the hypothesis that mean strength is 3500 psi. Use α-001. b) What is the smallest level of significance at which you coulji be willing to reject the...
(5 noints):Q1: Tensile strength tests were performed on two different grades of aluminum spars used in commercial a...
(5 noints):Q1: Tensile strength tests were performed on two different grades of aluminum spars used in commercial aircraft. From past experience with spar manufacturing process, the standard deviation of tensile strengths are assumed to be known. The data obtained are shown in table below. Find the 90% confidence interval on the difference in mean strength 1H2 Spar Sample Sample Mean Tensile Standard Deviation Grade size Strength (kg/mm) (kg/mm2) -87.6 n«10 ơ,-1.0 2 n2-12 o 1.5 74.5
(5 noints):Q1: Tensile strength...
A construction firm thinks that it is receiving 100 steel pipes with an average tensile strength...
A construction firm thinks that it is receiving 100 steel pipes with an average tensile strength of 10,000 pounds per square inch(lbs p.s.i.).This is the mean,μ.The size of the sample was n=100.The firm also knows that the population standard deviation,sigma,σ,is 400 p.s.i.The firm chooses a confidence interval of 95 %.This is equivalent to a level of significance,α,of 5 %(.05),where the null hypothesis is H0:μ0=10,000 and the alternative hypothesis is H1:μ0≠10,000.The company does not know that the actual, average tensile strength...
A civil engineer wishes to see if the tensile strength of the steel will change if...
A
civil engineer wishes to see if the tensile strength of the steel
will change if it is exposed to extreme temperature. Six
rebars were pretested, and then they were exposed to the extreme
heat 6-week period. The results are shown in the table. Can
it be concluded that tensile strength has been change at α=0.10.
Assume the variable is approximately normally distributed.
Determine also the confidence interval at 90%.
8. A civil engineer wishes to see if the tensile...
8. A civil engineer wishes to see if the tensile strength of the steel will change...
8. A civil engineer wishes to see if the tensile strength of the steel will change if it is exposed to extreme temperature. Six rebars were pretested, and then they were exposed to the extreme heat 6-week period The results are shown in the table. Can it be concluded that tensile strength has been changed at a 0.10? Assume the variable is approximately normally distributed. Determine also the confidence interval at 90% Subject Before (x.) 210 235 208 190 172...
Please be neat and clear so that I can follow through. Thank You and thumps up....
Please be neat and clear so that I can follow through. Thank You
and thumps up.
A sample of N The sample mean was found to be 36.2 ksi and the sample standard deviation was found to be 2.4 ksi. 4. 15 steel tensile specimens were taken and the yield strength of each measured Calculate a prediction interval, at 95 % confidence, for the yield strength value of the next sample. Calculate a 95 % confidence interval for the true...
A synthetic fiber used in manufacturing carpet has tensile strength that is normally distributed with mean...
A synthetic fiber used in manufacturing carpet has tensile strength that is normally distributed with mean 75.5 psi and standard deviation 3.5 psi. Suppose we measure the sample mean for n independent samples How is the variance of the sample mean changed when the sample size is increased from n-9 to n 36? What does this imply about the relationship between sample size and our estimate of the mean (sample mean here)?
a synthetic fiber used in manufacturing carpet has tensile strength that is normally distributed usted with...
a synthetic fiber used in manufacturing carpet has tensile strength that is normally distributed usted with mean 75.5 psi and standard deviation 3.5 psi. find the probability that a random sample n=6 fiber specimens will have sample mean tensile strength that is between 75.25 and 75.75 psi
7-5. A synthetic fiber used in manufacturing carpet has tensile strength that is normally distributed with...
7-5. A synthetic fiber used in manufacturing carpet has tensile strength that is normally distributed with mean 520 KN/m² and standard deviation 25 KN/m². Find the probability that a ran- dom sample of n= 6 fiber specimens will have sample mean tensile strength that exceeds 525 KN/m².
Tensile strength tests were carried out on two different grades of wire rod, resulting in the...
Tensile strength tests were carried out on two different grades of wire rod, resulting in the accompanying data. Grade Sample Size Sample Mean (kg/mm2) Sample SD AISI 1064 m = 127 x = 106.9 s1 = 1.2 AISI 1078 n = 127 y = 126.8 s2 = 2.2 (a) Does the data provide compelling evidence for concluding that true average strength for the 1078 grade exceeds that for the 1064 grade by more than 10 kg/mm2? Test the appropriate hypotheses...
Pr。Ыет 12. An engineer who is studying the tensile strength of a steel alloy intended for use in golf club shafts knows that tensile strength is approximately normally distributed. A random sample of 12 specimens has a mean tensile strength of 3250 psi and a sample standard deviation of 8-60 psi. a) Test the hypothesis that mean strength is 3500 psi. Use α-001. b) What is the smallest level of significance at which you coulji be willing to reject the...
(5 noints):Q1: Tensile strength tests were performed on two different grades of aluminum spars used in commercial aircraft. From past experience with spar manufacturing process, the standard deviation of tensile strengths are assumed to be known. The data obtained are shown in table below. Find the 90% confidence interval on the difference in mean strength 1H2 Spar Sample Sample Mean Tensile Standard Deviation Grade size Strength (kg/mm) (kg/mm2) -87.6 n«10 ơ,-1.0 2 n2-12 o 1.5 74.5
(5 noints):Q1: Tensile strength...
A
civil engineer wishes to see if the tensile strength of the steel
will change if it is exposed to extreme temperature. Six
rebars were pretested, and then they were exposed to the extreme
heat 6-week period. The results are shown in the table. Can
it be concluded that tensile strength has been change at α=0.10.
Assume the variable is approximately normally distributed.
Determine also the confidence interval at 90%.
8. A civil engineer wishes to see if the tensile...
8. A civil engineer wishes to see if the tensile strength of the steel will change if it is exposed to extreme temperature. Six rebars were pretested, and then they were exposed to the extreme heat 6-week period The results are shown in the table. Can it be concluded that tensile strength has been changed at a 0.10? Assume the variable is approximately normally distributed. Determine also the confidence interval at 90% Subject Before (x.) 210 235 208 190 172...
Please be neat and clear so that I can follow through. Thank You
and thumps up.
A sample of N The sample mean was found to be 36.2 ksi and the sample standard deviation was found to be 2.4 ksi. 4. 15 steel tensile specimens were taken and the yield strength of each measured Calculate a prediction interval, at 95 % confidence, for the yield strength value of the next sample. Calculate a 95 % confidence interval for the true...
A synthetic fiber used in manufacturing carpet has tensile strength that is normally distributed with mean 75.5 psi and standard deviation 3.5 psi. Suppose we measure the sample mean for n independent samples How is the variance of the sample mean changed when the sample size is increased from n-9 to n 36? What does this imply about the relationship between sample size and our estimate of the mean (sample mean here)?
7-5. A synthetic fiber used in manufacturing carpet has tensile strength that is normally distributed with mean 520 KN/m² and standard deviation 25 KN/m². Find the probability that a ran- dom sample of n= 6 fiber specimens will have sample mean tensile strength that exceeds 525 KN/m².
Most questions answered within 3 hours.
-
What is the NPV?
r=9.28
c1= 5.853
c2= 6.37 + 1,826.76
asked 12 seconds ago -
Please think of 2 on line only retailers that might benefit from
a brick and mortar...
asked 46 minutes ago -
The definition of a partition
function involved a sum over all states, and knowledge of the...
asked 1 hour ago -
Which of the following events would be considered Systematic?
(Choose all that apply.)
A. The Federal...
asked 2 hours ago -
Questions of this part analyze the students’ understanding in
analyzing the given scenario and practical skills...
asked 2 hours ago -
#C++
Write a function, named sortByCourseNumber, that takes a
reference to a vector of string (like...
asked 2 hours ago -
A
cylunder of titanium (length = 5.00cm, diameter = 1.20 cm) has a
mass of 25.5...
asked 3 hours ago -
1) Answer Each question with 1-2 Sentences:
a) How can we use the continuity and change...
asked 4 hours ago -
5. What is the decimal equivalent of the largest binary
integer that can be obtained with...
asked 3 hours ago -
Why is the magnitude of the Type Ia supernova always the same
(-19.6)?
asked 3 hours ago -
5. You are a quality control engineer and you are
asked to analyze the lifetime (in hours)...
asked 4 hours ago -
How many ways can 2 people be chosen and arranged in a straight
line if there...
asked 5 hours ago