Question: Oil Output - An energy official claims that the oil output per well in the United States has declined from the 1998 level of 11.1 barrels per day. He randomly samples 50 wells throughout the United States and determines the mean output to be 10.7 barrels per day. Assume that σ = 1.3 barrels. Test the researcher’s claim at the a = 0.05 level of significance.