Question

In: Statistics and Probability

A certain type of thread is manufactured with a mean tensile strength is 78.3kg, and a...

A certain type of thread is manufactured with a mean tensile strength is 78.3kg, and a standard deviation is 5.6kg. Assuming that the strength of this type of thread is distributed approximately normal, find: a) The probability that the mean strength of a random sample of 10 such thread falls between 77kg and 78kg. b) The probability that the mean strength greater than 79kg. c) The probability that the mean strength is less than 76kg. d) The value of X to the right of which 15% of the mean computed from random samples of size 10 would fall.

Solutions

Expert Solution


Related Solutions

A certain type of yarn is manufactured under specifications that the mean    tensile strength must be 22...
A certain type of yarn is manufactured under specifications that the mean    tensile strength must be 22 psi. A random sample of 26 units out of a population of 60 units yields a mean tensile strength of 20 psi and a standard deviation of 4.8 psi. Can we conclude from the data that the true mean tensile strength is less than 22 psi? If the random sample of 26 units were collected from a large population  with  the same mean and standard deviation,...
In an experiment involving the breaking strength of a certain type of thread used in personal...
In an experiment involving the breaking strength of a certain type of thread used in personal flotation devices, one batch of thread was subjected to a heat treatment for 60 seconds and another batch was treated for 120 seconds. The breaking strengths (in N) of ten threads in each batch were measured. The results were 60 seconds: 43 52 52 58 49 52 41 52 56 58 120 seconds: 59 55 59 66 62 55 57 66 66 51 Let...
In an experiment involving the breaking strength of a certain type of thread used in personal...
In an experiment involving the breaking strength of a certain type of thread used in personal flotation devices, one batch of thread was subjected to a heat treatment for 60 seconds and another batch was treated for 120 seconds. The breaking strengths (in N) of ten threads in each batch were measured. The results were 60 seconds: 43 52 52 58 49 52 41 52 56 50 120 seconds: 59 55 59 66 62 55 57 66 66 51 Let...
In an experiment involving the breaking strength of a certain type of thread used in personal...
In an experiment involving the breaking strength of a certain type of thread used in personal flotation devices, one batch of thread was subjected to a heat treatment for 60 seconds and another batch was treated for 120 seconds. The breaking strengths (in N) of ten threads in each batch were measured. The results were 60 seconds:     43    52    52    58    49    52    41    52    56    58 120 seconds:   59    55    59    66    62    55    57    66    66    51 Let...
)      A thread manufacturer test a sample of eight lengths of a certain type of thread...
)      A thread manufacturer test a sample of eight lengths of a certain type of thread made of blended materials and obtains a mean strength of 8.2 lb with standard deviation 0.06 lb. Assuming tensile strengths are normally distributed, construct a 90% confidence interval for the mean tensile strength of this thread.
An engineer studying the tensile strength of a composite material knows that tensile strength is approximately...
An engineer studying the tensile strength of a composite material knows that tensile strength is approximately normally distributed with σ = 60 psi. A random sample of 20 specimens has a mean tensile strength of 3450 psi. (a) Test the hypothesis that the mean tensile strength is 3500 psi, using α = 0.01 (b) What isthe smallest level of significance at which you would be willing to reject the null hypothesis? (c) What is the β error for the test...
An engineer who is studying the tensile strength of a steel alloy knows that tensile strength...
An engineer who is studying the tensile strength of a steel alloy knows that tensile strength is approximately normally distributed with sigma= 60 psi. A random sample of 12 specimens has a mean tensile strength of 3450 psi. a) Compute a two-side confidence interval on the maen tensile strength at a 95% confidence level. b) Test the hypothesis that the mean strength is 3500 psi at alfa=0.05, and provide a conclusion statement. c) If we keep the signifiance level constant...
An engineer who is studying the tensile strength of a steel alloy knows that tensile strength...
An engineer who is studying the tensile strength of a steel alloy knows that tensile strength is approximately normally distributed with σ = 60 psi. A random sample of 12 specimens has a mean tensile strength of 3450 psi. a) Compute a two-sided confidence interval on the mean tensile strength at a 95% confidence level b) Test the hypothesis that the mean strength is 3500 psi at α= 0.05, and provide a conclusion statement
: Determine the LRFD tensile design strength and the ASD tensile strength of the connection shown...
: Determine the LRFD tensile design strength and the ASD tensile strength of the connection shown if eight 7/8-in bolts are used in each flange to connect W18 X 76 with two 3/4 X 14-in plates. Include block shear calculations. (Fy = 50 ksi, Fu = 65 ksi)
It is known that the thread life of a certain type of tire has a normal...
It is known that the thread life of a certain type of tire has a normal distribution with standard deviation of 1500. a) A sample of 16 tires is found to have an average thread life of 30960. Does this provide sufficient evidence at 1% level of significance to conclude that the true average thread life of this type of tires is more than 30000? Explain by carrying out an appropriate hypothesis test stating clearly the hypotheses. b) What is...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT