Center for Freelance Writing: Dow Jones and S&P 500 Daily Change Correlations

Do the daily fluctuations in one stock index align well with the change observed in another index? For this exercise, let's take the Dow Jones and S&P 500 index for April 2012. For each index, after extracting the closing numbers for each day, the daily percentage change was computed, summarized below:

Date	Dow %Δ	S&P %Δ
30-Apr-12	-0.11%	-0.39%
27-Apr-12	0.18%	0.24%
26-Apr-12	0.87%	0.67%
25-Apr-12	0.69%	1.36%
24-Apr-12	0.58%	0.37%
23-Apr-12	-0.78%	-0.84%
20-Apr-12	0.50%	0.12%
19-Apr-12	-0.53%	-0.59%
18-Apr-12	-0.63%	-0.41%
17-Apr-12	1.50%	1.55%
16-Apr-12	0.56%	-0.05%
13-Apr-12	-1.05%	-1.25%
12-Apr-12	1.41%	1.38%
11-Apr-12	0.70%	0.74%
10-Apr-12	-1.65%	-1.71%
9-Apr-12	-1.00%	-1.14%
5-Apr-12	-0.11%	-0.06%
4-Apr-12	-0.95%	-1.02%
3-Apr-12	-0.49%	-0.40%
2-Apr-12	0.40%	0.75%

Average	0.004%	-0.034%
Stand Dev	0.008693038	0.009248878