Testing a Hypothesis about a Population Mean: Small Sample The “fun size” of a Snickers bar is supposed to weigh 20 grams. Because the penalty for selling candy bars under their advertised weight is...

Testing a Hypothesis about a Population Mean: Small Sample

The “fun size” of a Snickers bar is supposed to weigh 20 grams. Because the penalty for selling candy bars under their advertised weight is severe, the manufacturer calibrates the machine so the mean weight is 20.1 grams. The quality-control engineer at M&M–Mars, the Snickers manufacturer, is concerned about the calibration. He obtains a random sample of 11 candy bars, weighs them, and obtains the data in Table 1. Should the machine be shut down and calibrated? Because shutting down the plant is very expensive, he decides to conduct the test at the α = 0.01 level of significance.