People are confused as to how to sit shiva and how to properly pay a shiva call. Because people do not know, and because talking about death makes people nervous and awkward, the shiva house often turns into a festive gathering filled with nervous chatter, instead of the proper house of mourning.
The average number of days in a month is around 30.4. With 24 hours in a day, this is an average of about 730 hours per month.
Or you could say that three of every four years has 365 days, for a mean of 365/12 days per month and one in four has 366 for a mean of 61/2 days per month. The weighted mean of those is 3/4 x 365/12 + 1/4 x 61/2 = 487/16 ~ 30.4375.