**General Mathematics, Vol. 4, 1996 **

**Abstract:** The following problem may be formulated: {\it by using only the
frequency and the mean to find mean deviation}. In the last years many authors have
obtained the exact mean deviation of some discrete distributions. A good source of
references is A.R. Kamat$\!'$s report (1963). Here we solve the above problem in the case
of the following continuous distributions: Gamma, $\chi^{2}$ and Beta. As an application,
the exact probability of a certain event is given in a convenient form.

**Classification (MSC91): 60E05**

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