Comment: Here's your answer:rho =

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Here's your answer:rho =

Here's your answer:

rho = ~0.5
pval = ~1e-10

I used weekly data sourced from the Fed's balance sheet (specifically, the H.4.1 release located at: http://www.federalreserve.gov/releases/h41/) and weekly data sourced from a bitcoin website (located at: http://bitcoincharts.com/).

It is worth noting that the last weekly amount available for bitcoin is for April 8th; therefore, I think the correlation would weaken a bit as we have seen a gigantic run-up (and run-down for that matter) in the past few days that will not be reflected in the Fed's balance sheet.