Reference no: EM132157558

Metal ions affect the homeostasis of Alzheimer's disease (AD) patients. Khanahmadi et al. conducted a study to compare the metal ions iron, zinc and copper in patients with AD with the normal range provided by the laboratory. Among a group of 17 patients with AD in Tehran's aging centers in 2015, blood samples were collected and analyzed for iron, zinc and copper in a pathobiological laboratory. Results are provided in the table below (units are in μg/dL).

Metal Ion n Sample Mean Standard Error Normal Range

Iron 17 55.76 4.75 37-145

Zinc 17 64.35 3.27 80-120

Copper 17 119.29 5.61 80-155

Using a 0.01 significance level, you need to test the claim that this sample comes from a population with a mean zinc level that is significantly less than 80 μg/dL (i.e., the lower limit of the normal range).

1) What critical value should you use to test the given hypothesis? a. -2.326 b. -2.567 c. -2.576 d. -2.583 e. -2.921 f. None of the above because we need 2 critical values (one positive and one negative)