A company employs two shifts of workers. Each shift produces a type of gasket where the thickness is the critical dimension. The average thickness and the standard deviation of thickness for shift 1, based on a random sample of 37 gaskets, are 9.64 mm and 0.15 mm. The similar figures for shift 2, based on a random sample of 35 gaskets, are 9.66 mm and 0.18 mm. Let _{1 2} be the mean difference in thickness between shifts 1 and 2.

Calculate a 95% confidence interval for _{1 2}. Round your answers to three decimal places, if necessary.

Lower limit
Upper limit