You are designing an electrical heater that will use the 120V AC line voltage available in houses. the heater will be used to heat water in an insulated vessel. You use a 3.5-digit sultimeter which has a manufacturer's stated accuracy of +-1.5% full scale and +-5 in the last digit. Say you use the 200V range on the meter and make the following measurements of the AC voltage over the course of the day (all values in AC volts):
117.3 121
114.1 115.9
119.9 116.2
121.6 122.7
122.6 121.5
a) what is the instrument uncertainty?
b) what is the total uncertainty of the next measurement(95% confidence)
c) what is the total uncertainty of the mean of your sample compared to the population mean (assuming 95% confidence)?