Suppose that 100 random samples of water from a freshwater lake were taken and the calcium concentration (milligrams per liter) measured. A 95% confidence interval on the mean calcium concentration,

u, is (0.49, 0.82). If we are to increase the sample size to 180 (other factors remain unchanged), the 95% confidence interval for u would: O be the same. O become narrower. O be impossible to determine. become wider.