The manufacturer of a refrigerator system for beer kegs produces refrigerators that are supposed to maintain a true mean temperature, , of 48F, ideal...

The manufacturer of a refrigerator system for beer kegs produces refrigerators that are supposed to maintain a true mean temperature, μ, of 48°F, ideal for a certain type of German pilsner. The owner of the brewery does not agree with the refrigerator manufacturer, and claims he can prove that the true mean temperature is incorrect.