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# st: RE: Assistance if possible

 From "Martin Weiss" To Subject st: RE: Assistance if possible Date Wed, 10 Mar 2010 21:54:15 +0100

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Welcome to the Stata community! What is your question, though???

HTH
Martin

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Saint Joseph
Sent: Mittwoch, 10. März 2010 20:45
To: majordomo@hsphsun2.harvard.edu
Cc: statalist@hsphsun2.harvard.edu
Subject: st: Assistance if possible

I will like to join the stata group as well as find a way to solve the problem below:
I calculate the highest 24-month concentration of merger bids involving firms in that industry in each decade.2 This 24-month period is identified as a potential wave. Taking the total number of bids over the entire decade for a given industry, I simulate 1000 distributions of that number of occurrences of industry member involvement in a bid over a 120-month period by randomly assigning each occurrence to a month where the probability of assignment is 1/120 for each month. I then calculate the highest 24-month concentration of activity from each of the 1000 draws. Finally, I compare the actual concentration of activity from the potential wave to the empirical distribution of 1000 peak 24-month concentrations. If the actual peak concentration exceeds the 95th percentile from that empirical distribution, that period is coded as a wave. For example, 36% of the 161 bids in the health care industry in the 1990s occurred within one 24-month period starting
in May of 1996. Out of 1000 simulated distributions of 161 bids across a 10-year period, the 95th percentile of maximum concentration within any 24-month period is 27%. Thus, the cluster of bids in the health care industry starting in May of 1996 is coded as a wave.”

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