Unfortunately, arsenic occurs naturally in some ground water. A mean arsenic level of mu equals 8.0 parts per billion (ppb) is considered safe for agricultural use. A well in Texas is used to water...

Unfortunately, arsenic occurs naturally in some ground water. A mean arsenic level of mu equals 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 test gave a sample mean of x-bar = 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? Alpha = 0.01.

a)  What is the level of significance?

b)  What is the value of the sample test statistic?   Round answer to 3 decimal places.

c) estimate the p-value?