How would this question concerning confidence interval be assessed?

It is claimed that a new diet will reduce a person's weight by 4.5 kilograms on average in a period of 2 weeks. The weights of 7 women who followed this diet were recorded before and after the 2-week period. Test the claim about the diet by computing a 90% condence interval for the mean difference in weights. Assume the differences of weights to be approximately normally distributed. Click here to view the data set. Click here to view page 1 of the table of critical values of the t-distribution. Click here to view page 2 of the table of critical values of the t-distribution. Let p1 be the population mean for Weight Before and let [.12 be the population mean for WeightAfter. The condence interval is