The level of dissolved oxygen in a river is an important indicator of the waters ability to support aquatic life. You collect water at 15 samples randomly chosen locations a long a stream and measure the dissolved oxygen. Here is the results in milligram per liter :

4.53, 5.04,3.29,5.23,4.13,5.50,4.83,4.40, 5.42,6.38,4.01,4.66,2.87,5.73,5.55< br />
Test to determine if the level of dissolved oxygen in this river is below the 5.4 milligrams per liter that is recommended by the US Fish and Wildlife Service. Carry out an appropriate test of this claim at the
α=0.05 level.

1. State the hypotheses and identify the claim.

2. Given an α=0.05, what type of test is used (left tailed, right tailed or two-sided tail) and what is the critical t-value?

3. Compute the test value.

4. Make the decision.

5. Summarize the results.