max k not X'es before
X rth time P(X)=p
: r p:
The probability of maximum 4 failures before the 5th success
is calculated. Probability of success is 0.4.
The example may be the drawing of balls from a hat that con-
tains 40% white balls. The probability of finding 5 not white
balls before drawing maximum 4 white balls is calculated.
The probability of the rth success in kth trial in a series of in-
dependent trials is calculated.