Billiard table all six pockets), with rounded entrances and nearly parallel sides, like those on a snooker table. One tactical consequence of this design difference is that the jaws of the WPA-type pocket are often used exactly like a horizontal version of the backboard of a basketball goal, to rebound the ball into the pocket; this technique does not work on blackball tables, and even shots down the cushion into a corner pocket are more difficult. For tournament competition under WPA world-standardized rules (and league play under derived rulesets), the bed of the pocket billiard table must be made of slate no
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