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A research article investigates the compressive strength of concrete when mixed with fly ash fa mixture of silica, alumina, iron, magnesium oxide, and other ingredients) The compressive strength for nine samples in dry conditions on the 28th day are as follows (in megapascals]: 40.2, 30.4, 28.9, 30.5, 22.4, 25 8, 18.4, 14.2, and 15.3. The sample mean and standard deviation are 25.122 and 8.42, respectively. 1. Find the 95% two-sided confidence interval on the mean compressive strength. 2. Find a $9% lower confidence bound on the compressive strength variance, 3. Find an interval that will contain 99% of the values of the compressive strength with 95% confidence. 4. Test the hypothesis that the mean compressive strength is 27 megapascals using 5%% level of significance. 5. Is there strong evidence to conclude that the standard deviation in this experiment exceeds 10? Use (7 = 0.05. 6. Based on 5, suppose that the true standard deviation is 11, The researcher would like to detect the difference with a probability of at least 90%%, Is the used sample size adequate? Justify your