The following data represent the muzzle velocity? (in feet per? second) of shells fired from a? 155-mm gun. For each? shell, two measurements of the velocity were recorded using two different measuring? devices, resulting in the following data.
Observation 1 2 3 4 5 6
A 794.1 790.3 791.3 793.7 793.6 792.2
B 800.6 787.8 801.0 793.6 803,1 796.0
Construct a? 99% confidence interval about the population mean difference. Compute the difference as device A minus device B. Interpret your results.
The confidence interval is: ?