[Two-sample t-test] The steel rods supplied by two different companies were compared. Ten sample springs were made out of the steel rods supplied by each company and the bounciness was studied. The data are as follows: (Assume that the population variances are equal) Company A: 9.3 8.8 6.8 8.7 8.5 6.7 8.0 6.5 9.2 7.0 Company B: 11.0 9.8 9.9 10.2 10.1 9.7 11.0 11.1 10.2 9.6 (a) Setup two hypotheses. (b) Can you conclude that there is virtually no difference between the steel rods supplied by the two companies? Use a p-value to reach your conclusion.
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Let μ1 be the mean bounciness of steel rods from Company A and μ2 be the mean bounciness of steel rods from Company B. Null hypothesis (H0): There is no difference between the steel rods supplied by the two companies, i.e., μ1 = μ2. Alternative hypothesis (H1): Show more…
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Adi S.
In a study, steel rods supplied by two different companies were compared. Springs were made out of the steel rod supplied by each company, and the "bounciness" was studied. Company A 9.3 8.8 6.8 8.7 8.5 6.7 8.0 8.8 6.5 9.2 7.0 Company B 11.0 9.8 9.9 10.2 10.1 9.7 11.0 11.1 10.2 10.2 9.6 On 0.10 level of significance, can we conclude that the population variances in the steel rods supplied by these companies are equal? Assume both population are approximately normal. Show all your work.
10.112 In a study conducted by the Department of Mechanical Engineering and analyzed by the Statistics Consulting Center at the Virginia Polytechnic Institute and State University, the steel rods supplied by two different companies were compared. Ten sample springs were made out of the steel rods supplied by each company and the "bounciness" was studied. The data are as follows: Company A: $$\begin{array}{llllllllll}9.3 & 8.8 & 6.8 & 8.7 & 8.5 & 6.7 & 8.0 & 6.5 & 9.2 & 7.0\end{array}$$ Company B: $\begin{array}{llllllllll}11.0 & 9.8 & 9.9 & 10.2 & 10.1 & 9.7 & 11.0 & 11.1 & 10.2 & 9.6\end{array}$ Can you conclude that there is virtually no difference in means between the steel rods supplied by the two companies? Use a P-value to reach your conclusion. Should variances be pooled here?
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