A study of iron deficiency among infants compared samples of infants following different feeding regimens. One group contained breast-fed infants, while the infants in another group were fed a standard baby formula without any iron supplements. Here are summary results on blood hemoglobin levels at 12 months of age: Group n X S Breast-fed 23 13.3 1.7 Formula 19 12.4 1.8 Is there significant evidence that the mean hemoglobin level is higher among breast-fed babies? Follow the steps listed below: (i) Define the parameter of interest. (ii) State the null and alternative hypotheses; use a two-sided test. (iii) State the assumptions for the standard ("pooled") two-sample t-test in this context. (iv) Compute the test statistic. Show your work clearly. State the null distribution of the test statistic. (v) Find the P-value; explain briefly how you found it. (You may use a table of the t distribution, or R.) (vi) State your conclusion: Do you reject or fail to reject Ho? What does this result tell you about the comparison between breast-feeding and formula?