A chemical production process uses water-cooling to carefully control the temperature of the system so that the correct products are obtained from the resulting chemical reaction. The temperature of the system must be maintained at a temperature of 120 degrees Fahrenheit. A technician suspects that the average temperature is different from 120 degrees Fahrenheit and checks the process by taking temperature readings at 12 randomly selected times over a 4-hour period. Here are the data:

120.1 124.2 122.4 124.4 120.8 121.4

121.8 119.6 120.2 121.5 118.7 122.0

Is there convincing evidence at the
α
α=0.05 significance level that the true mean temperature
μ
μ of the system is different from 120 degrees Fahrenheit?