The June precipitation (in inches) for 10 randomly selected cities are listed below. Construct a 90% confidence interval for the population standard deviation, σ. Assume the data are normally distributed.
2.0 3.2 1.8 2.9 0.9 4.0 3.3 2.9 3.6 0.8
◦ (0.81, 1.83)
◦ (0.53, 1.01)
◦ (1.10, 2.01)
◦ (0.32, 0.85)