Series. Attendance at the third World Series game recording the age of each fan. For the following examples in Exercises, indicate whether the data are a time series or a cross section.

If false, explain why.

a) We can eliminate sampling error by selecting an unbiased sample.

b) Randomization helps to ensure that our sample is representative.

c) Sampling error refers to sample-to-sample differences and is also known as sampling variability.

d) It is better to try to match the characteristics of the sample to the population rather than relying on randomization.