Add a location to your Tweets. When you tweet with a location, Twitter stores that location. You can switch location on/off before each Tweet and always have the option to delete your location history. Learn more.
Cluster sampling examples. Example 1: Assume that a study with relatively large square fixed area plots of 50 m x 50 m had been carried out, on which all tree positions were mapped. Because the individual plots were relatively large, there were only resources available to measure \(n=10\) sample plots.
Cluster sampling refers to a sampling method that has the following properties. 1  The population is divided into N groups, called clusters. 2  The researcher randomly selects n clusters to include in the sample. 3  The number of observations within each cluster Mi is known, and M = M1 + M2 + M3 + ... + MN-1 + MN.