The database commonly uses an index range scan to access selective data. The selectivity is the percentage of rows in the table that the query selects, with 0 meaning no rows and 1 meaning all rows. Selectivity is tied to a query predicate, such as WHERE last_name LIKE 'A%', or a combination of predicates.
Types of Distribution: Intensive, Selective and Exclusive Distribution. Some of the important types of distribution in international market are 1. Intensive 2. Selective and 3. Exclusive distribution.
To summarize: 1.) the sampling distribution is a theoretical distribution of a sample statistic. 2.) There is a different sampling distribution for each sample statistic. 3.) Each sampling distribution is characterized by parameters, two of which are and. The latter is called the standard error.