A manufacturer of alloy steel beams requires that the standard deviation of yield strength not exceed 7000 psi. The quality-control manager selected a sample of 20 beams and measured their yield strength. The standard deviation of the sample was 7500 psi. Assume that the yield strengths are normally distributed. Does the evidence suggest that the standard deviation of yield strength exceeds 7000 psi at the a = 0.01 level of significance? Complete parts (a) through (d) below. (a) Determine the null and alternative hypotheses. Ho 7000 psi H1: 7000 psi (b) Calculate the P-value. P-value = (Round to three decimal places as needed.) (c) State the conclusion for the test. Choose the correct answer below. O A. Reject Ho because the P-value is less than the a = 0.01 level of significance. O B. Reject Ho because the P-value is greater than the a = 0.01 level of significance. O C. Do not reject Ho because the P-value is greater than the a = 0.01 level of significance. O D. Do not reject Ho because the P-value is less than the a = 0.01 level of significance. (d) State the conclusion in context of the problem. There sufficient evidence at the a = 0.01 level of significance to conclude that the standard deviation of yield strength exceeds 7000 psi