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.
Usually, the known value is a population mean. The dependent variable is normally distributed. Null: There is no significant difference between the sample mean and the population mean. Alternate: There is a significant difference between the sample mean and the population mean. Go to Analyze menu, choose Compare Means, then One-Sample T Test. Move the dependent variable into the  Test Variables  box.