Find Best-Fit-Line and Correlation Between Two Tables in Microsoft Access?

Question

I have two queries in a Microsoft Access database. They are named Average and Home_Runs. They both share the same first three columns Name, [Year] and Month.

Query: Average

Name    Year    Month   Average  
Cabrera  2013   5       .379 
Fielder  2013   5       .245 
Martinez 2013   5       .235  
Cabrera  2013   6       .378  
Fielder  2013   6       .278 
Martinez 2013   6       .240 

Query: Home_Runs

Name    Year    Month   Home Runs  
Cabrera  2013   5       12 
Fielder  2013   5       2
Martinez 2013   5       2 
Cabrera  2013   6       9  
Fielder  2013   6       4 
Martinez 2013   6       4 

I need to offset the data before I begin the calculations. I need to determine how the Home Runs from one month relate the the Average from the previous month. So it is not a direct month-to-month comparison. I need to perform a month-to-previous-month comparison.

I need to do two calculate two things from these two queries.

First: With Average being the X-axis and Home_Runs being the Y-Axis. I need to find the correlation between these data points.

Second: With Average being the X-axis and Home_Runs being the Y-Axis. I need to find the equation of the best-fit-line between all of these data points. More specifically I need to find the value of the Y variable when the X variable equals certain values.

Additional Information:

In the end I need to return a table that looks like this:

Calculation            Tier 1   Tier 2  Tier 3  Correlation 
Avgerage to Home Runs  .04      3.00    6.00    .80

What is the best way to accomplish these things?

Answer 1

Here is the SQL Fiddle example for you to play with and tweak to get it exactly right:

SELECT (Avg(A.Paverage * H.HomeRuns) - Avg(A.Paverage) * Avg(H.HomeRuns)) /     
    (StDevP(A.Paverage) * StDevP(H.HomeRuns)) AS Correlation,
    (Sum(A.Paverage * H.HomeRuns) - (Sum(A.Paverage) * Sum(H.HomeRuns) / 
    Count(*))) / (Sum(A.Paverage * A.Paverage) - (Sum(A.Paverage) * Sum(A.Paverage) / Count(*))) AS LineBestFit
FROM Averages AS A 
   INNER JOIN Home_Runs AS H 
   ON (A.Pname = H.Pname) 
   AND (A.Pyear = H.Pyear) 
   AND ((A.Pmonth - 1) = H.Pmonth)