Reference no: EM132905953

The data set (Concrete1.xlsx) contains the compressive strength, in thousands of pounds per square inch (psi), of 30 samples of concrete taken two and seven days after pouring. (a) At the 0.05 level of significance, is there evidence of a difference in the mean strengths at two days and at seven days? Show the work: i) your hypotheses, ii) test statistic, iii) critical value, and iv) decision. (b) Find the p-value in (a) and interpret its meaning. (c) At the 0.05 level of significance, is there evidence that the mean strength is lower at two days than at seven days? Show the work: i) your hypotheses, ii) test statistic, iii) critical value, and iv) decision. (d) Find the p-value in (c) and interpret its meaning.