.Calcium is essential to tree growth because it promotes the formation of wood and maintains cell walls. In​ 1990, the concentration of calcium in precipitation in a certain area was 0.11 milligrams per liter​ (mg/L). A random sample of 10 precipitation dates in 2007 results in the following data table.
Construct 90​% confidence interval about the sample mean concentration of calcium precipitation.
the lower bound is
the upper bound is
Data table
0.079 0.078 0.088 0.246 0.123
0.179 0.125 0.218 0.338 0.102