For that you need 2 data pieces:
- The median pay of chinese workers in Yuan.
- The Yuan - Us Dollar cross currency exchange rate.
You then use the second to convert the first into US Dollars so that you compare the Chinese salaries in USD to American salaries is USD.
Merely the second piece of data wIthout the first means nothing if you're trying to compare salaries.
For example, before the Euro the Italian Lira used to have a cross currency exchange rate with the dollar which was thousands of lire per dollar and that didn't mean Italians in the 80s were incredibly poor: because for every dollar the average US worker received in their salary the average Italian worker got thousands of lire, all put together mean they got about 1/2 to 1/3 of a US salary rather that the 1/1000 that by your the exchange rate alone suffices "logic".
By the way, that cross currency exchange rates are meaningless to compare incomes or costs without the actual incomes and prices in the local currency, is really, really, REALLY basic financial knowledge.