The breaking strength of yarn supplied by two manufacturers is being investigated. We know from experience...

The breaking strength of yarn supplied by two manufacturers is being investigated. We know from experience with the manufacturers’ processes that σ1 = 5 psi and σ2 = 4 psi. A random sample of 20 test specimens from each manufacturer results in x¯1 = 88 psi and x¯2 = 91 psi.

(a) Show all steps (including how to find cutoff value) and construct a two-sided 90% Confidence Interval for the true difference in means. Draw a conclusion on whether yarn 1 and yarn 2 are significantly different using only the confidence interval constructed.

(b) Show all steps (including how to find cutoff value) and construct a two-sided 95% Confidence Interval for the true difference in means. Draw a conclusion on whether yarn 1 and yarn 2 are significantly different using only the confidence interval constructed.

Solutions

Expert Solution

( a )

yarn 1 and yarn 2 are significantly different because 0 does not lies between -5.355 and -0.645

( b )

yarn 1 and yarn 2 are significantly different because 0 does not lies between -5.806 and -0.194

orchestra answered 1 year ago

Next > < Previous

Related Solutions

The breaking strength of yarn used in the manufacture of woven carpet material is Normally distributed...

The breaking strength of yarn used in the manufacture of woven carpet material is Normally distributed with 2.4 psi (pound-force per square inch). A random sample of 16 specimens of yarn from a production run were measured for breaking strength and a confidence interval for the breaking strength of yarn was found to be (128.7, 131.3). (a) What is the confidence level, C, of this interval? A. 90% B. 92% C. 95% D. 96% E. 97% F. 98.5% G. 99%...

The breaking strength of yarn used in the manufacture of woven carpet material is Normally distributed...

The breaking strength of yarn used in the manufacture of woven carpet material is Normally distributed with σ = 2.4 psi. A random sample of 16 specimens of yarn from a production run was measured for breaking strength, and based on the mean of the sample (x bar), a confidence interval was found to be (128.7, 131.3). What is the confidence level, C, of this interval? Please show work and explain A. 0.95 B. 0.99 C. 0.90 D. 0.97 E....

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 compressive strength of concrete is being studied, and four different mixing techniques are being investigated....

The compressive strength of concrete is being studied, and four different mixing techniques are being investigated. The following data have been collected to test if the mixing techniques affect the strength of the concrete. Mixing Technique Compressive strength (psi) A 3125 3200 2800 2600 B 3000 3300 2900 2700 C 2865 2975 2985 2600 D 2890 3150 3050 2765 a. Find the summary statistics for compressive strength of each mixing technique. b. State the null and alternative for the above...

Two types of plastics are suitable for use by an electronics component manufacturer. The breaking strength...

Two types of plastics are suitable for use by an electronics component manufacturer. The breaking strength of these plastics is very important. From a random sample size of n1=18, and n2=16, we obtained that X1-bar=151.2, S1=1.4 and X2-bar=152.3, S2=1.65. Calculate a 95% confidence interval on the ratio of variances. With 95% confidence, what is the right-value of the two-sided confidence interval on the ratio of variances? Your Answer: Two types of plastics are suitable for use by an electronics component...

Two types of plastic are suitable for use by an electronic calculator manufacturer. The breaking strength...

Two types of plastic are suitable for use by an electronic calculator manufacturer. The breaking strength of the plastic is important. From random samples of n1 = 10 and n2 = 12 batches the respective means were obtained as ¯y1. = 152.5 and ¯y2. = 153.7. The total sum of square for the data was SSTotal = 31.865. (a) Complete the following ANOVA table. Source SS df MS F Treatment Error - Total 31.865 (b) Calculate the t statistic for...

Two kinds of thread are being compared for strength.

A. Two kinds of thread are being compared for strength. Fifty pieces of each type of thread are tested under similar conditions. Brand A had an average: tensile strength of 78.3 kilograms with a standard deviation of 5.6 kilograms, while brand B had an average tensile strength of 87.2 kilograms with a standard deviation of 6.3 kilograms. Construct a 95% confidence interval for the difference of the population means.B. In a hatch chemical process, two catalysts arc being compared for...

Urban planners in Melbourne average 10.2 years’ experience. We know this from a Census of urban...

Urban planners in Melbourne average 10.2 years’ experience. We know this from a Census of urban planners, but the raw data was lost, so we cannot use the data to compute σ. What an inconvenience! (a) In a random sample of 65 urban planners in Melbourne’s growth areas, the average was 8.7 years with a standard deviation of 0.52. Are growth-areas planners significantly less experienced than the metropolitan average? Presume alpha = 0.05 (b) The same sample of urban...

Data and logic flow are key to the “user experience” as we know it to be...

Data and logic flow are key to the “user experience” as we know it to be today. Website user experience is important for analysts to develop a high “user return” rate. This is accomplished by a positive user experience due to positive web interface development. What website design principles do you think are most important when capturing and presenting data interactively? Why? Comment from personal experience about using or designing sites. What mistakes do you feel are most often made...

The breaking strength of hockey stick shafts made of two different graphite-kevlar composites yields the following...

The breaking strength of hockey stick shafts made of two different graphite-kevlar composites yields the following results (in Newtons): Composite 1: 479 505.3 471.1 488.6 467.2 483.4 491.1 481.2 480.7 484.5 470.9 480 472.6 485.4 469.1 482.2 478.2 490.7 468.1 (Note: The average and the standard deviation of the data are respectively 480.5 Newtons and 9.6 Newtons.) Composite 2: 506 521 474.4 496.6 517.5 506.3 511.3 486.9 499.3 466.4 507.3 527 (Note: The average and the standard deviation of the...

Subjects