Unfortunately, arsenic occurs naturally in some ground water. A mean arsenic level of = 8.0 parts per billion (ppb) is considered safe for agricultural use. A well in Texas is used to water cotton crops. This well is tested on a regular basis for arsenic. A random sample of 36 tests gave a sample mean of x = 6.7 ppb arsenic, with s = 3.0 ppb. Does this information indicate that the mean level of arsenic in this well is less than 8 ppb? Use = 0.01. (a) What is the level of significance? 0.01 State the null and alternate hypotheses. H0: = 8 ppb; H1: < 8 ppb H0: = 8 ppb; H1: 8 ppb H0: < 8 ppb; H1: = 8 ppb H0: > 8 ppb; H1: = 8 ppb H0: = 8 ppb; H1: > 8 ppb