According to a University of Florida wildlife ecology and conservation researcher, the average level of mercury uptake in wading birds in the Everglades is declining (UF News, December 15, 2000). Last year, the average level was 15 parts per million.

a. Give the null and alternative hypotheses for testing whether the average level today is less than 15 ppm.

b. Describe a Type I error for this test.

c. Describe a Type II error for this test.

a)

Null hypothesis: μ=15

Alternative hypothesis: μ<15

b)

Type I error is rejecting the null hypothesis that average level was 15 parts per million while it was actually 15 parts per million.

c)

Type II error is not rejecting the null hypothesis that average level was 15 parts per million while it was actually less than 15 parts per million.

Step-by-step explanation:

a.

The null hypothesis always constitutes of equality and alternative hypothesis constitutes of inequality. We are given that last year the average level of mercury uptake in wading birds in the Everglades is 15 ppm. The study shows that it is declining. Thus, we are interested in testing the average level today is less than 15 ppm. Thus, the null and alternative hypothesis are

Null hypothesis: μ=15

Alternative hypothesis: μ<15

b.

Type I error can be described as the rejecting of true null hypothesis.

Type I error in the given scenario can be described as the rejecting the null hypothesis that average level was 15 parts per million while it was actually 15 parts per million.

c.

Type II error can be described as the not rejecting the incorrect null hypothesis.

The type II error is not rejecting the null hypothesis that average level was 15 parts per million while it was actually less than 15 parts per million.