Arsenic is a compound naturally occurring in very low concentrations. Arsenic blood concentrations in healthy individuals are normally distributed with mean = 3.2 micrograms per deciliter ( g/dl) and standard deviation = 1.5 g/dl. Some areas are known to have naturally elevated concentrations of arsenic in the ground and water supplies. We take a simple random sample of 25 adults residing in a high-arsenic areas.

1.State the three simple conditions/assumptions in order to conduct a one sample z-test. Do the 3 simple conditions hold true in this study

2. We seek evidence against the claim that = 3.2. What is the sampling distribution of the mean blood arsenic concentration x-bar in many samples of 25 adults if the claim is true? Sketch the density curve of this distribution.

3.We suspect that the average blood arsenic concentration of all adults in this high arsenic area will not be 3.2 g/dl. State the null and alternative hypothesis.

4.The data from this sample give the mean blood arsenic concentration x-bar = 3.75 g/dl. In order to test the hypothesis in (c), calculate 95% confidence interval, interpret the 95% CI in this context. What can we conclude?

5.Using significance level of = 0.05, calculate P-value for this study? Interpret P-value in this context. What can we conclude?