How to use analyst opinions to invest in equities?

For the past few days, I have been trying to assess the correlation of analyst rating of companies and the profitability of the companies' equities. It is a very common trend that companies' equities show a positive movement in their stocks if they announce a profit in the recent quarter. This trend to anologous to the value of sports players or actors. If an actor gives a block buster movie, his value (Salary for the next movie) increases exponentially. I pulled data about 9 companies that announced their earnings last week. From Yahoo finance, I pulled data about analyst opinions and provided scores based on their ratings.

Please find the excel sheet attached below:

Name of the company	Ticker	Total Score	No of analysts	Avg	Rating	Stock movement	Result
Teekay Corporation	NYSE: TK	5	9	0.56	BUY	2.00%	1.00
Cal Dive International	NYSE: DVR	3	5	0.60	BUY	12.00%	1.00
Duke Energy Corporation	NYSE: DUK	3	11	0.27	HOLD	-0.60%	0.00
FirstEnergy Corp.	NYSE: FE	6	21	0.29	HOLD	3.03%	1.00
Energy Transfer	NYSE: ETP	5	16	0.31	HOLD	1.96%	0.00
Huntington Ingalls	NYSE: HII	6	14	0.43	HOLD	-2.94%	(1.00)
Dean foods company	NYSE: DF	6	11	0.55	BUY	6.21%	1.00
Prudential Financial	NYSE: PRU	20	20	1.00	BUY	-5.41%	(1.00)
Metallico	NYSE: MEA	0	1	0.00	HOLD	-6.82%	(1.00)

** In Result Column, we are looking at BUY/SELL recommendation based on the stock movement. A value 1, 0 and -1 corresponds to a BUY, HOLD and SELL recommendation correspondingly

Based on the ratings and the stock movement on the day earnings were announced, we were able to made the following observations:

First, if the analyst opinions lead to a BUY, can we say that we are certain to reap a profit?

Quite often, analysts are right with their judgment for the winners. Except for Prudential, BUY rated stocks are winners. This could be a sandy effect. Sandy was a big shock for insurance companies. If we receive a BUY or STRONG BUY rating from analysts, It is a good idea to go ahead and buy the stock. But, we cannot say that the analysts are highly precise. For example, if you sort the analysts' scores from the smallest to largest, this would not correspond to the profiitability of the stocks (or) about 50% of the stocks are in sync to this order.

Second, let me talk about HOLD ratings, HOLD ratings leads to be the profitability being unpredictable. Except for Metallico, 50% of the HOLD rated stocks are profitable. Whereas, the other 50% led to a loss.

Third, We dont have any companies with a SELL rating here. Since the data involved in this research was really limited, we are not making any comments here.  

Fourth, I beleive we need to have a sample size of atleast five analysts to use their data to make any kind of conclusion.

Last, all of the big winners are captured here as BUY Stocks. This prepares us to using this analysis to come up with an investment strategy.

This is the investment strategy that I propose:
Check for the analyst ratings of companies that are going to announce their earnings. BUY equities of companies that have a BUY or STRONG BUY rating (on an average) from most of the analysts. This should present a good investment opportunity.