In order to ?nd out whether children with chronic diarrhea have the same average hemo- globin level (Hb) that is normally seen in healthy children in the same area, a random sample of 10 children with chronic diarrhea are selected and their Hb levels (g/dL) are obtained as follows.
12.3 11.4 14.2 15.3 14.8 13.8 11.1 15.1 15.8 13.2
Do the data provide suf?cient evidence to indicate that the mean Hb level for children with chronic diarrhea is less than that of the normal value of 14.6 g/dL? Test the appropriate hypothesis using α = 0.01. Draw a box plot and normal plot for this data, and comment.