Question

Nitrate, an inorganic chemical, is a drinking water contaminant which is considered safe for human consumption as long as Nitrogen levels in the water are under 10 MCLG. A local library near a sewage plant is concerned that their public water fountain “tastes funny,” and they hypothesize that sewage runoff has affected the quality of their water. An EPA worker randomly tests 40 one-ounce samples of drinking water at the public water fountain and finds that the mean Nitrogen content is 10.33 MCLG with a standard deviation of 2 MCLG. Using a significance level of 0.0l, you need to test the claim that the population mean is not equal to 10 MCLG. Assume the amounts follow a bell-shaped distribution.

1. We fail to reject the null hypothesis. We have sufficient evidence to re-test the claim.
2. We reject the null hypothesis. We do not have enough evidence to support the claim.
3. We reject the null hypothesis. We have enough information to support the claim.
4. We fail to reject the null hypothesis. We do not have sufficient evidence to support the claim.
5. We fail to reject the null hypothesis. We have enough evidence to support the claim.

Answer 1

DATE 1I Va ce P-Vatce 03001 ha ㄚ š no sufficeent, ev.una l- Suplt e claim