Refer to Exercise 8.77. The researcher selects two groups of 400 subjects each and collects the following sample information on the annual beef consumption now and 10 years ago:

a. The researcher would like to show that per-capita beef consumption has decreased in the last 10 years, so she needs to show that the difference in the averages is greater than 0. Find a 99% lower confidence bound for the difference in the average per-capita beef consumptions for the two groups.
b. What conclusions can the researcher draw using the confidence bound from part a?

Sample Mean Sample Standard Deviation Ten Years Ago 73 25 This Year 63 28