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 = 6.9 ppb arsenic, with s = 2.6 ppb. Does this information indicate that the mean level of arsenic in this well is less than 8 ppb? Use = 0.01.

What is the level of significance?

What is the value of the sample test statistic? (Round your answer to three decimal places.)