I am not sure that the answer i chose is correct, so could you please help me check about that as well?

Consider a study to determine the compressive strength of concrete blocks used for paving. Two methods of manufacturing concrete blocks are under investigation method A (which is more expensive) and method B. Research indicates that the greater the compressive strength of concrete, the greater the durability of a concrete block. Therefore the question is, which one, if either, of the two methods produces greater compressive strength. In addition, the manufacturer considers that an average difference between the methods of less than 500 psi (pounds per square inch) would be of no consequence, whereas a difference of 500 psi or more could result in considerable benets. Some possible outcomes of the study are: sebQ-g) P-value 95% Cl Case 1 3.55 0.0000 (42, 56) Case 2 29.24 0.0233 (-124, -8) Case 3 -30 19.92 0.1305 (-70, 10) Case 4 536 11.28 0.0000 (513, 559) Case 5 100 303.05 0.7435 (-506, 706) Note: The hypotheses associated with the quoted P-values are: H0: There is no difference in the mean compressive strength of concrete blocks when using the two methods of manufacture. H1: There is a difference in the mean compressive strength of concrete blocks when using the two methods of manufacture. Et- a) What is the hypothesised value? [ Select ] b) Select the correct options to complete the sentence about Case 1: The estimated mean in Case 1 (XA-XB = 49) is 43.37 (2d.p.) standard errors below the hypothesised value. c) Which case(s) demonstrate, at the 5% level of significance, that the observed mean, x, is statistically different from the hypothesised value? Cases 3 and 5 d) In which case(s) are we are able to claim that the difference between the true mean compressive strengths for method A and method B: - has practical significance [ Select ] - does not have practical significance [ Select ] e) Select one case in which we have learned nothing useful [ Select ] Vfl Suppose the actual outcome for the study is: 573 14.83 0.0000 (543, 603) Select the correct option to complete the sentences interpreting this output: In this case the difference between the true mean compressive strengths for method A and method B [Select] V statistically signicant (at the 5% level). We [Select] V able to claim that the difference between the true mean compressive strengths has practical importance. With 95% condence the mean compressive strength using method A is estimated to be somewhere between [SeIECt] V and [Select] V [Select] V than the mean compressive strength using method B. Based on these results I would [Select] V