A soap factory's quality-control inspector randomly selects 15 bars of soap for analysis.The 15 bars contain a mean of 200 g of sodium stearate, with a standard deviation of 12 g.From this sample, the inspector constructs a 99% confidence interval of the mean sodium stearate content of the factory's soap bars.What is the margin of error of that confidence interval?Assume that the sodium stearate content of the soap bars is approximately normally distributed.Answer to 4 decimal places.