I need assistance with these questions I have until 9pm to complete. Thanks. Identify the population and the sample then describe the sampling method...

I need assistance with these questions I have until 9pm to complete. Thanks.

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. Give a reason for 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

Gomez           Hernandez     Huang      Kim 

Liao                Mourning        Naber       Peters

Pliego             Puri                 Richards   Rogers

Santiago       Shen                 Vega          Wang

4. Researchers investigated the effect 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.