14. Healthy Eating Has the consumption of red meat decreased over the last 10 years? A researcher selected hospital nutrition records for 400 subjects surveyed 10 years ago and compared the average amount of beef consumed per year to amounts consumed by an equal number of subjects interviewed this year. The data are given in the table.

a. Do the data present sufficient evidence to indicate that per-capita beef consumption has decreased over the last 10 years? Test at the 1% level of significance.

b. Find a 99% lower confidence bound for the difference in the average per-capita beef consumptions for the two groups. Does the confidence bound confirm your conclusions in part a? Explain. What additional information does the confidence bound give you?

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Sample Mean Sample Standard Deviation Ten Years Ago This Year 223 73 25 63 28