Does Attendence effect Winning in MLB

I started messing with this idea over the weekend because I like to watch TV and play with the computer at the same time. I was looking at various stats on MLB on the ESPN website, and I ended up looking at the various teams home field attendance numbers. There really are few surprises in the top ten, half are American League and half are National League with all except the Twins, Cubs and Dodgers having good seasons.

The bottom ten was more of a surprise to me. with 70% of those teams with poor attendance from the American League and Division Leader Cleveland Indians right there at 26th place. The Indians draw poorly both home and anyway.

This got me thinking if there is an impact of the mythical 11th man (or 10th man in the National League). So I thought I would look at if variations in attendance impacts the Indians performance on the field. The spreadsheet below shows the results for the first half of the 2011 season. It is interesting to note that the Indians have a much better record when attendance is less than 10,000 (6-1) or more than 30,000 (7-1) than they do when attendance is between 10,000-20,000 (10-7) or 20,000-30,000 (4-2). Correlation is not causality, but at least for this year the Indians do better when the 11th man shows or stays home, and worse when he kinda shows.

Attendance	Runs scored	Runs Allowed	Run Diff
8726	7	1	6
9025	3	1	2
9076	8	2	6
9523	8	4	4
9650	9	4	5
9722	7	2	5
9853	3	8	-5
10594	1	0	1
10714	8	3	5
13017	4	2	2
13551	5	4	1
14164	5	4	1
15224	7	8	-1
15278	4	6	-2
15336	2	11	-9
15397	4	7	-3
15498	1	0	1
15568	9	5	4
15849	2	3	-1
15877	3	4	-1
16336	2	8	-6
16346	8	2	6
17568	4	3	1
18107	4	7	-3
19225	3	2	1
20261	0	2	-2
23752	2	4	-2
26408	2	14	-12
26433	3	2	1
26833	12	4	8
27458	0	4	-4
30023	5	2	3
31622	5	4	1
31865	5	1	4
33774	5	4	1
38549	5	1	4
40631	2	1	1
40676	6	3	3
41721	10	15	-5