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.
The Normal Distribution. In your statistical travels you'll come across two major types of random variables: discrete and continuous. Discrete random variables basically count things (number of heads on 10 coin flips, number of female Democrats in a sample, and so on). The most well-known discrete random variable is the binomial. (See Chapter 8 for more on discrete random variables and binomials).