A machine produces pipes used in airplanes. The average length of the pipe is 16 inches....

A machine produces pipes used in airplanes. The average length of the pipe is 16 inches. The acceptable variance for the length is 0.3 inches. A sample of 17 pipes was taken. The average length in the sample was 15.95 inches with a variance of 0.4 inches.

a.	Construct a 95% confidence interval for the population variance.
b.	State the null and alternative hypotheses to be tested.
c.	Compute the test statistic.
d.	The null hypothesis is to be tested at the 5% level of significance. State the decision rule for the test using the critical value approach.
e.	What do you conclude about the population variance?

Solutions

Expert Solution

milcah answered 10 months ago

Next > < Previous

Related Solutions

A pipes manufacturer makes pipes with a length that is supposed to be 19 inches. A...

A pipes manufacturer makes pipes with a length that is supposed to be 19 inches. A quality control technician sampled 24 pipes and found that the sample mean length was 19.08 inches and the sample standard deviation was 0.24 inches. The technician claims that the mean pipe length is not 19 inches. What type of hypothesis test should be performed? What is the test statistic? What is the number of degrees of freedom? Does sufficient evidence exist at the α=0.01...

A pipe is manufactured according to a process that produces 1 defective pipe per 5000 pipes...

A pipe is manufactured according to a process that produces 1 defective pipe per 5000 pipes produced. All pipes produced are subject to an x-ray inspection. 99.9% of all defective pipes fail the inspection (are correctly identified as defective). 0.2% of good pipes fail the inspection (are incorrectly identified as defective). 1)What is the probability that a randomly-selected pipe will fail the inspection? (E.g. enter 50% as 0.50.) 2) What is the probability that a pipe that passes the inspection...

5. A company produces metal pipes of a standard length, and claims that the variance of...

5. A company produces metal pipes of a standard length, and claims that the variance of the length is 1.44 cm. One of its clients decide to test this claim by taking a sample of 25 pipes and checking their lengths. They found that the standard deviation of the sample is 2.4 cm. Does this undermine the company’s claim? A. State the hypotheses b. Find the calculated value of the test statistic c. Find the critical value at α =...

A) Machine A produces an average of 10% of defective parts. Machine B produces on average...

A) Machine A produces an average of 10% of defective parts. Machine B produces on average twice as many defective parts as machine A. Machine C produces on average three times more defective parts than machine B. Here are 8 bags of parts from A, 2 bags of parts from B and 1 bag of coins from C. We randomly take a coin from one of the bags itself also taken at random. She is defective. 1. What is the...

A. Find the length of an organ pipe closed at one end that produces a first...

A. Find the length of an organ pipe closed at one end that produces a first overtone frequency of 276 Hz when air temperature is 21.3ºC . B. Find the length of an organ pipe closed at one end that produces a first overtone frequency of 276 Hz when air temperature is 21.3ºC . C. Electromagnetic radiation having a 73.8 μm wavelength is classified as infrared radiation. What is its frequency in 1013 Hz? D. Find the intensity of an...

According to a recent study, the average length of a newborn baby is 19.219.2 inches with...

According to a recent study, the average length of a newborn baby is 19.219.2 inches with a standard deviation of 1.21.2 inch. The distribution of lengths is approximately Normal. Complete parts (a) through (c) below. Include a Normal curve for each part. A.The probability that a baby will have a length of 20.4 inches or more is B. The probability that a baby will have a length of 21.5 inches or more C. The probability that a baby will have...

A machine produces metal rods used in automobile suspension system. A random sample of 16 rods...

A machine produces metal rods used in automobile suspension system. A random sample of 16 rods is selected, and the diameter measured. The resulting data in millimeters are shown here: 8.23 8.58 8.42 8.18 8.86 8.25 8.69 8.27 8.19 8.96 8.33 8.34 8.78 8.32 8.68 8.41 Calculate a 90% confidence interval on the diameter mean. With 90% confidence, what is the right-value of the confidence interval on the diameter mean?

5. The length of needles produced by a machine has standard deviation of 0.02 inches. Assuming...

5. The length of needles produced by a machine has standard deviation of 0.02 inches. Assuming that the distribution is normal, how large a sample is needed to determine with a precision of ±0.006 inches the mean length of the produced needles to 98% confidence?

A steel factory produces iron rods that are supposed to be 36 inches long. The machine...

A steel factory produces iron rods that are supposed to be 36 inches long. The machine that makes these rods does not produce each rod exactly 36 inches long. The lengths of these rods vary slightly. It is known that when the machine is working properly, the mean length of the rods is 36 inches. According to design, the standard deviation of the lengths of all rods produced on this machine is always equal to .05 inches. The quality control...

Lazurus Steel Corporation produces iron rods that are supposed to be 36 inches long. The machine...

Lazurus Steel Corporation produces iron rods that are supposed to be 36 inches long. The machine that makes these rods does not produce each rod exactly 36 inches long. The lengths of the rods are normally distributed and vary slightly. It is known that when the machine is working properly, the mean length of the rods is 36 inches. The standard deviation of the lengths of all rods produced on this machine is always equal to 0.035 inch. The quality...

Subjects