The Healthy Eating Index measures on a 100-point scale the adequacy of consumption of vegetables, fruits, grains, milk, meat and beans, and liquid oils. This scale is called HEI2005 (Guenther et al.2007). There are two interviews for each person in the study. The first interview is identified by daycode = 1 and the second interview is identified by daycode = 2. This data is stored in the data file HEI Cost Data Variable Subset. Find a 95% confidence interval estimate of the difference in the mean HEI-2005 scores between male and female participants at the time of their first interview.