Blackball (pool) number "8" (a holdover from kelly pool), though numberless variants are not unknown. British pool tables come in 6 × 3 foot (1.8 × 0.9 m) or 7 × 3.5 ft (2.12 × 1.06 m) varieties, with 7 feet being the regulation size for league play. The table has pockets just larger than the balls and rounded, as in the game of snooker, whereas the international-style (or "American-style") table has pockets significantly wider, with pointed . Tournament rules may require the presence of more than one type of (mechanical bridge), as in snooker. There are two competing standards bodies that
Standard normal table the standard normal table to find probabilities. Normal distributions are symmetrical, bell-shaped distributions that are useful in describing real-world data. The "standard" normal distribution, represented by the letter Z, is the normal distribution having a mean of 0 and a standard deviation of 1. If "X" is a random variable from a normal distribution with mean μ and standard deviation σ, its Z-score may be calculated from X by subtracting μ and dividing by the standard deviation: For the average of a sample of size n from some population in which the mean is μ and the standard deviation is