Suppose a real estate agent is interested in comparing the asking prices of condos in Montreal and Halifax. The agent conducts a small telephone survey in the two cities, asking the condo prices. A random sample of20listings in Montreal resulted in a sample average price of $345,000, with a standard deviation of $14,700. A random sample of27listings in Halifax resulted in a sample average price of $350,000, with a standard deviation of $13,500. The agent assumes condo prices are normally distributed and the variance in prices in the two cities is about the same.

If the agent obtains a 90% confidence interval for the difference in mean condo prices between Montreal and Halifax, what is the lower value of the interval?