Stocks Update: PFE Sold Today, 1.3% in One Day

I sold the 2000 shares of Pfizer today that I bought yesterday, netting a 1.3% gain. Thus far, my short-term trades have been 100% successful, while my other trades have a mixed record. Some of the ongoing debates in the stock market are as follows:

a) Does active trading reduce gains?
b) Can investors time the market?; and
c) Do long-term investors always do well if they buy-and-hold for several years?

Conventional wisdom would say "Yes" to (a) and (c), and "No" to (b). One of the reasons I disclose my trades is to see whether the conventional wisdom is actually correct. Warren Buffett and Charlie Munger believe that investors can time the market and view the "efficient market hypothesis" (i.e., all public information is immediately factored into a company's stock price, making it almost impossible to time the market) with disdain. Thus far, I am in the Berkshire camp. But we will see as the years go by.

Open Positions
CNB = -5.40
EQ = -5.54
EWM = -1.17
GE = -3.75
ICE = -2.11
IF = -6.53
PFE = -7.64
PNK = -2.97
PPS = 0
WYE = -3.52

Total: losing/negative average of 4.29%

Closed Positions:
Daytrades: PFE (+0.5%)

Held less than 7 days: MMM (0.5%), MRK (0.1%), PFE (1.3%), SCUR (15%) (Overall record in this category is a 4.23% average gain)

Total: up/positive 3.48%