4.2 The following 10 measurements of the freezing point of aluminum were made using a platinum/rhodium thermocouple. 658.2 659.8 661.7 662.1 659.3 660.5 657.9 662.4 659.6 662.2 Find (a) the median, (b) the mean, (c) the standard deviation, and (d) the variance of the measurements. 4.7 A pressure control system in a distillation column is designed to maintain the pres- sure at a constant value of 10.9 bar. The following 10 pressure readings (in bars) were obtained at intervals of 10 min: 10.7 11.0 11.2 10.8 10.6 11.1 10.9 10.8 10.7 11.0 Determine the mean and standard deviation of the pressure measurements.