State the null and alternative hypothesis Draw a diagram labeling the appropriate critical values and shaded regionFind the test statistic State the conclusion

20. Unfortunately, arsenic occurs naturally in some ground water. A mean arsenic level of u=8.0 parts per billion is considered safe for agricultural use. A well in Batavia N.Y. is used to water corn crops. This well is tested on a regular basis for arsenic. A random sample of 15 tests gave a sample mean x=7.2 ppb arsenic with s=1.9 ppb. Does this information indicate that the mean level of arsenic in this well is less than 8 ppb? Use a=1%