An environmental researcher is concerned that a new industrial plant has made the water in a nearby stream more acidic. The pH measures the amount of acidity or alkalinity of a substance (Pure water would have a pH of 7, numbers lower than 7 indicate acids, numbers greater than 7 indicate alkaline bases). The researcher collects 40 water samples and has found an average pH of 5.9. The researcher would like to conduct a test of hypothesis to determine if the water is significantly acidic.

Select all of the correct null and alternative hypotheses

A) H0: mu = 0B) H0: mu = 7C) H0: mu cannot equal 7D) H0: mu = 0E) HA: mu cannot equal mu0F) HA: mu < 7G) HA: mu > 7H) HA: mu < 0