Question

In: Statistics and Probability

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 μX represent the population mean for threads treated for 120 seconds and let μY represent the population mean for threads treated for 60 seconds. Find a 99% confidence interval for the difference μX−μY . Round down the degrees of freedom to the nearest integer and round the answers to three decimal places.

The 99% confidence interval is

Solutions

Expert Solution

-------------------------------------------------------------------------------------------------------------------------


Related Solutions

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 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...
I need explanation for this problem: The breaking strength of a certain type of fabric has...
I need explanation for this problem: The breaking strength of a certain type of fabric has mean 1.86 and standard deviation .2. A random sample of 49 pieces of fabric is drawn. A- What is the probability that the sample mean breaking strength is less than 1.8? B- How large a sample size is needed so that the probability is .06 that the sample mean is less than 1.8? Ans for (A)= 0.02 Ans for (B)= 27
Previous experience has shown that the breaking strength of the fabric used in a certain brand...
Previous experience has shown that the breaking strength of the fabric used in a certain brand of drapes is normally distributed with a standard deviation of 2 pounds per square inch. A random sample of 9 specimens is examined to reveal an average breaking strength of x = 98 pounds per square inch. Determine the p−value required to test the hypothesis that the true mean is not 97.
The breaking strength X of a certain rivet used in a machine engine has a mean...
The breaking strength X of a certain rivet used in a machine engine has a mean 5000 psi and standard deviation 400 psi. A random sample of 25 rivets is taken. Consider the distribution of ?̅, the sample mean breaking strength. (a) What is the probability that the sample mean falls between 4800 psi and 5200 psi? (b) What sample n would be necessary in order to have P(4950 < ?̅<5050) = 0.95 (0.99)?
Q6. Chitin is used to produce a certain type of surgical thread. a) What physical and...
Q6. Chitin is used to produce a certain type of surgical thread. a) What physical and chemical properties make it an ideal material for this purpose? b) Propose another product that chitin could be used for in everyday life. c) Why should products made of Chitin be relatively inexpensive to mass produce? Q7. Why do proteins have more diverse functional role in a cell than do carbohydrate? Q8. Why do the elements 8,16,and 34 belong to the same family on...
Data analysis of the breaking strength of a certain fabric shows that it is normally
Data analysis of the breaking strength of a certain fabric shows that it is normally distributed with a mean of 300 lb and a variance of 9. a. Estimate the percentage of fabric samples that will have a breaking strength no less than 294 lb. b. Estimate the percentage of fabric samples that will have a breaking strength no less than 297 lb and no greater than 303 lb.
)      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.
The specifications for a certain kind of ribbon call for a mean breaking strength of 185...
The specifications for a certain kind of ribbon call for a mean breaking strength of 185 pounds. Suppose five pieces are randomly selected from different rolls. The breaking strengths of these ribbons are 171.6, 191.8, 178.3, 184.9 and 189.1 pounds. You are required to perform an appropriate hypothesis test by formulating the null hypothesis µ = 185 against the alternative hypothesis test µ < 185 at α = 0.10. (i) What is the critical region for the test? (ii) What...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT