"In order to estimate the mean neck length of a certain species of giraffe, a researcher collects a sample of 4 giraffes of that species and finds the mean neck length to be 9 ft, with standard deviation 2.1 ft. Find a 99% confidence interval for the mean neck length of a giraffe. Assume that the neck lengths are normally distributed. The confidence interval is of the form (a,?b). What is the value of b?" answer correct to 3 decimals