October 23, 2009

median age

I think you remember learning in school that  there are three type of averages - mean, mode and median.

It was reported that the median age of the stall-holders in the wet market is 60.

That means if you line up all the stall-holders from the youngest to the oldest, the middle one is 60 years old. It also means there is an equal number of stall-holders above and below him.

My perception of this is that the stall-holders are not all old people waiting to retire. There are also many younger ones in their thirties or forties.

If it says that the mean age is 60, I would think that most of them are older people. (mean = total ages of all the stall-holders divided by the total number of stall-holders)

If the modal age is 60, it tells us that stall-holders with the age of 60 form the largest group. Again I think it would give the impression that stall-holders are mostly old people.

Eye drops
See this bottle of eye-drops, you have to throw it away 1 month after opening. One month has passed and I used it on one occasion only. I was thinking what else I could use it for ... For the past few days I have been using it to clean my spectacle lenses. It does the job quite well. Any other suggestions?

1 comment:

Miko said...

wow.. ur age theory is very chim