Arsenic is a compound naturally occurring in very low concen

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.

We suspect that the average blood arsenic concentration in this high arsenic areas will be higher than 3.2 g/dl. State the null and alternative hypothesis in this situation. Can we use 95% CI to test this new hypothesis? Conduct an appropriate test for this hypothesis using significance level of =0.05. What can we conclude?

Solution

a)

State the null and alternative hypothesis in this situation.

Ho: u <= 3.2 g/dL
Ha: u > 3.2 g/dL [ANSWER]

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b)

Can we use 95% CI to test this new hypothesis?

YES, but we should use a lower endpoint 0.95 confidence interval. [ANSWER]

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c)

Conduct an appropriate test for this hypothesis using significance level of =0.05. What can we conclude?

Hi! Please resubmit this question, and include the other data given in the problem for us to conduct this test so that we can perform the test, the data here is insufficient. Thanks!