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In: Statistics and Probability

A sample of n = 20 specimens of cold-processed steel bars was taken to measure their...

A sample of n = 20 specimens of cold-processed steel bars was taken to measure their strength. The average resistance of the sample was 29.8 ksi, while the sample standard deviation was 4.0 ksi. A second sample consisting of 25 galvanized steel bars was also evaluated. The average resistance for this second sample was 34.7 ksi. and the sample standard deviation was 5.0 ksi.

Assuming that the data comes from normal distributions and that the variances cannot be assumed to be the same:

a.Determine if there is evidence to conclude that the means of the two populations are different. Express your conclusion clearly _ clearly state the hypotheses you are testing, the areas of acceptance and rejection, the test statistician and express your conclusion in complete sentence.


b. Calculate the p-value. Explain how to use the p-value to conclude.

c. Would it have been reasonable to assume equal variances?

Solutions

Expert Solution

Solution:

The concept of hypothesis testing and the testing of two population means along with nature of the test statistic and it's distribution for various cases is needed as a prerequisite to understand the solution to the given problem. The solution is given below:

orchestra answered 1 year ago
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