An engineer wants to know if the mean strengths of three different concrete nix

Question

An engineer wants to know if the mean strengths of three different concrete nix designs differ significantly. He randomly selects 9 cylinders that measures 6 inches in diameter and 12 inches in height in which mixture A is poured, 9 cylinders of mixture B, and 9 cylinders of mixture C. After 28 days, he measures the strength (in pounds per square inch) of the cylinders. The results are presented in the accompanying table. State the null alternative hypothesis. Choose the correct answer below. H_0: mu_A = mu_0 = mu_C and H_1: at least one of the means is different H_0: mu_A = mu_B = mu_C and H_1: mu_A = mu_B = mu_C H_0: mu_A = mu_B and H_1: the means are different

Explanation / Answer

Null hypothesis assumes equality and therefore the correct answer is A since it is considering all A B and C

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