1 Polyps: Benign growths in the uterine lining (endometrium) can cause a heavy or prolonged period. 2  Ovary dysfunction: Lack of ovulation (anovulation) results in a lack of progesterone, causing heavy periods. 3  Adenomyosis: When glands from the uterine lining embed in uterine muscle, heavy bleeding can occur.
Mean and Variance of Random Variables. The mean of a random variable provides the long-run average of the variable, or the expected average outcome over many observations.
For example; 'income' is a variable that can vary between data units in a population (i.e. the people or businesses being studied may not have the same incomes) and can also vary over time for each data unit (i.e. income can go up or down). A continuous variable is a numeric variable.