I have until 9pm to complete the following:

Identify the population and the sample then describe the sampling method that was used:

1. A machinery manufacturer purchases voltage regulators from 10 different suppliers. There are reports that variation in the output voltage of regulators is affecting the performance of the finished products. To assess the quality of the suppliers' production, the manufacturer sends a random sample of 5 regulators from each of his suppliers' last shipments to a lab for study.

Determine if the study is an experimental or observational study. Givea reasonfor your answer:

2. A medical researcher is interested in testing a new medicine for migraine headaches. She selects an SRS of 100 adults who get migraines at a rate of one or

more per week. Half of the selected adults will receive the new medicine while half will receive a placebo. The researcher will compare all results.

Use the random digit table to answer the following:

3. You are asked to construct an interview of 6 randomly selected employees at your company to answer insurance questions. Use the random digit table starting at line 139 to choose 6 of the following individuals to be interviewed.

Agarwal Anderson Baxter Bonds

Bowman Castillo Cross Dewald

Fernandez Fleming Gates Goel

GomezHernandez Huang Kim

Liao MourningNaber Peters

Pliego PuriRichards Rogers

Santiago Shen Vega Wang

4. Researchers investigated theeffect of listening to music by Mozart before taking an IQ test. Subjects were randomly assigned to one of three groups and would either listen to Mozart music, be told to relax, or be given no instructions. The sample mean IQ in Mozart group was 119, in the relax group was 111, and in the silent group was 110.

a. Is this an experiment or an observational study?

b. If it is an experiment, is it randomized or block design?

c. If it is an experiment, identify the explanatory and response variables.

d. If this is an experiment, draw a diagram representing the levels and treatments.