To compare the strength of two alloys, 10 independent random samples of each of the alloys were collected. Alloy A had a mean strength of 28,600 kN/m2 with a standard deviation of 6100 kN/m2, while Alloy B had a mean strength of 34,400 kN/m2 with a standard deviation of 5400 kN/m2. Assume the strengths of both alloys are normally distributed. Using a 10% significance level, determine if Alloy B is significantly stronger than Alloy A on average. You are not allowed to make other assumptions.
To compare the strength of two alloys, 10 independent random samples of each of the alloys...
1. Three different metal alloys were tested for tensile strength. The strength of some examples of each alloy measured (in hundreds of megapascals), as follows. was Alloy Tensile strength of some examples 19.8 12.4 1 15.2 14.8 2 8.9 11.6 10.0 11.9 3 10.5 13.8 12.1 Source: the data come from Berenson and Levine (1998), Business Statistics: A First Course, p. 449, Question 10.27, but shortened.) Taking the types of alloy one-way ANOVA. The following R commands were used: as...
There are two suppliers of gears. Tests were conducted on random samples of gears from the two suppliers to determine the impact strengths. Summary data are given in the table below. Sample Sample Supplier Sample Mean Standard 289.30 321.50 Deviation 22.5 21 Size 10 16 2 Let μ i be the true mean impact strength for Supplier l and μ2 be that for Supplier 2. Assume that impact strengths are normally distributed.
Problem 4 The strength of an aluminum alloy is normally distributed with mean 10 GPa and standard deviation 14 GPa. What is the probability that a specimen of this alloy will have a strength greater than 12 GPa? What is the 95th percentile of the strength of this alloy? a) b) Problem 4 The strength of an aluminum alloy is normally distributed with mean 10 GPa and standard deviation 14 GPa. What is the probability that a specimen of this...
The melting points of two alloys used in formulating solder were investigated by melting 21 samples of each material. The sample mean and standard deviation for alloy 1 was 420.48 and 2.34 respectively, and for alloy 2 they were 425 and 2.5 respectively. Do the sample data support the claim that both alloys have the same melting point? Use a fixed-level test with alpha=0.05 and assume that both populations are normally distributed and have the same standard deviation. Provide the...
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...
Two samples each of size 20 are taken from independent populations assumed to be normally distributed with equal variances. The first sample has a mean of 43.5 and a standard deviation of 4.1 while the second sample has a mean of 40.1 and a standard deviation of 3.2. A researcher would like to test if there is a difference between the population means at the 0.05 significance level. What can the researcher conclude? There is not sufficient evidence to reject...
Test the indicated claim about the means of two populations. Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal. Use the traditional method or P-value method as indicated. A researcher was interested in comparing the response times of two different cab companies. Companies A and B were each called at 50 randomly selected times. The calls to company A were made independently of the...
A study was designed to compare the attitudes of two groups of nursing students towards computers. Group 1 had previously taken a statistical methods course that involved significant computer interaction. Group 2 had taken a statistic methods course that did not use computers. The students' attitudes were measured by administering the Computer Anxiety Rating Scale (CARS). A random sample of 15 nursing students from Group 1 resulted in a mean score of 41.5 with a standard deviation of 4.2. A...
Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal Refer to the accompanying data set. Use a 0.05 significance level to test the claim that women and me Click the icon to view the data for diastolic blood pressure for men and women Data for Diastolic Blood Pressure of Men and Women Let , be the mean diastolic blood pressure for women and let...
help 2. (5 pt) Assume that the two samples are independent simple random samples selected from normally distributed populations and do not assume that the population standard deviations are equal. a) Test the claim using the P-value method or critical value method b) Construct a confidence interval suitable for testing the following claim The following statistics are listed for IQ scores for a random sample of subjects with high levels and low levels of lead in their blood. Use a...