Section 1.3

11.Random samples.Explain how you would take a simple random sample of 8 students from a class with 40 students. (Note: Do not use method of picking numbers from a hat, or similar.)

12.What method of data collection should be used (census or sample)?A study exploring the weights of U.S. senators.

13.Explain.Under what circumstances is it best to use simulation to gather data?

14.Explain the meaning and state the reason.What is randomization, and what is the purpose for using it.

15.State the sampling technique used (stratified, random,cluster,convenience, or systematic).A company divides a large property into a grid pattern, assigning each square a unique number. A researcher randomly selects some of the squares in the grid, then measures and records a chemical level in every tree in each one.

16.State the sampling technique used (stratified, random,cluster,convenience, or systematic).A researcher divides the ages of people in a community into 4 groups: (1) less than 20 years old; (2) greater or equal to 20, but less than 40 years old; (3) greater or equal to 40, but less than 60 years old; and (4) greater than or equal to 60 years old. The researcher then takes a random sample from each group.

17.State the sampling technique used (stratified, random,cluster,convenience, or systematic).A researcher goes to a gravel pile, takes a shovel full of gravel, and then measures the volume of each stone.

18.State the sampling technique used (stratified, random,cluster,convenience, or systematic).At the grand opening of a new Walmart, every 10th person in a line is selected and given a door prize.