I don't know why you thought otherwise, but the weights are
applied to the medians too. In 1997, for example, as a total
weight of 200 is assigned to .5 and a total weight of 197 is
assigned to higher values, .5 emerges as the median.
Nick
n.j.cox@durham.ac.uk
Eric G. Wruck
> I have mutual fund data on turnover & total net assets. Below you'll
> see an example:
>
>
> +-----------------------+
> | year turnover tna |
> |-----------------------|
> 1. | 1997 .5 200 |
> 2. | 1997 .73 172 |
> 3. | 1997 1.1 25 |
> 4. | 1998 .61 255 |
> 5. | 1998 .96 220 |
> |-----------------------|
> 6. | 1998 .85 75 |
> +-----------------------+
>
>
> I want to get an asset-weighted average turnover ratio as well as
> report median turnover.
>
> I issue the command:
>
> . collapse (mean) avgturn=turnover (median) medturn=turnover
> [aweight=tna], by(year)
>
> & obtain
>
> +---------------------------+
> | year avgturn medturn |
> |---------------------------|
> 1. | 1997 .6374307 .5 |
> 2. | 1998 .7827273 .85 |
> +---------------------------+
>
> The average turnover ratios are precisely what I want, but I don't
> understand what Stata is doing with the medians. I thought the
> weights wouldn't enter into the calculations & that I would obtain
> medians of 0.73 & 0.85 for 1997 & 1998. However, for 1997 I get a
> median turnover of 0.5. Would somebody kindly explain this to me?
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