Sampling Lab

The purpose of this laboratory exercise is to familiarize yourself with the different sampling techniques.

You need one page from a movie listing (like contained in TV-Guide). Note, if you actually use TV Guide®, then you need to use two facing pages. Pick a page with little extraneous material, other than the listings, on it.

For the purposes of this sampling project, a movie is included on the page or in a cluster if the running time for the movie falls on the page.

Random Sampling

Number each movie on the page. If there are a lot of movies, you may wish to number every other or every third movie.

Generate a random sample on 8 numbers between 1 and the number of movies on the page. Write down the # generated and the running time for the movie corresponding to that number.

Systematic Sampling

Generate a random number between 1 and 6. Beginning with the movie corresponding to that number, and then taking every 6th movie thereafter, write the # of the movie and the running length of the movie.

Convenience Sampling

Write down the running time of the first eight movies.

Stratified Sampling

On a separate piece of paper, write down the running times of all PG/PG13, R, and not-rated (either NR or no rating given) movies in three columns -- ignore all other types (NC17, G, etc). Split a sample of 8 proportionally to each type of movie (if R is 40%, then sample 40% of 8 = 3.2 -> 3 R movies). Use random sampling within each movie type. Record the running lengths of the movies selected.

Cluster Sampling

Divide the page into equal regions so that each region has roughly 3 - 4 movies in each cluster. Randomly select 3 clusters, and record the running length of all movies in those clusters.

Table of Contents