Researchers wanted to compare two anti-depressants A1 and A2 to see if there is an increase in the norepinephrine concentration in the brain. One group of 25 subjects, who took A1, had a mean norepinephrine concentration of 3 milligrams. Another group of 30 subjects, who took A2, had a mean norepinephrine concentration of 6 milligrams. Assume the population standard deviations of the concentrations in the people who take A1 and the people who take A2 are 1 milligram and 1.5 milligrams, respectively. Find the 90% confidence interval for the difference in concentrations between the people who take A1 and the people who take A2. Let the subjects who took A1 be the first sample, and let the subjects who took A2 be the second sample. Assume the samples are random and independent. Assume that both the population distributions are normally distributed. Round your answer to two decimal places. Do not include units in your answer.

Confidence Level	CorrespondingzcValue
90%confidence	zc=1.645
95%confidence	zc=1.96
99%confidence	zc=2.576