|
Group Statistics
|
|
|
Group
|
N
|
Mean
|
Std. Deviation
|
Std. Error Mean
|
|
Annual Income
|
Control Group
|
42
|
20813.7143
|
10578.81613
|
1632.34677
|
|
Experiment Group
|
42
|
22258.7619
|
8896.90632
|
1372.82245
|
|
Independent Samples Test
|
|
|
Levene's Test for Equality of Variances
|
t-test for Equality of Means
|
|
F
|
Sig.
|
t
|
df
|
Sig. (2-tailed)
|
Mean Difference
|
Std. Error Difference
|
95% Confidence Interval of the Difference
|
|
Lower
|
Upper
|
|
Annual Income
|
Equal variances assumed
|
1.563
|
.215
|
-.678
|
82
|
.500
|
-1445.04762
|
2132.88477
|
-5688.03487
|
2797.93964
|
|
Equal variances not assumed
|
|
|
-.678
|
79.659
|
.500
|
-1445.04762
|
2132.88477
|
-5689.90279
|
2799.80755
|
Hint: Mean difference Std error diff 95% Confidence Interval of the difference last 2 columns
|
-1445.04762
|
2132.88477
|
-5688.03487
|
2797.93964
|
|
1445.04762
|
2132.88477
|
-5689.90279
|
2799.80755
|
Discussion:
Q: In order to promote the habit of saving among low-income households, United Way of Greater Los Angeles conducted a pilot study in 2007 to determine the effectiveness of high-interest savings accounts by randomly selecting two groups of low-income savers. In this pilot, both groups were offered incentives to save every month, but one of the groups, (the experiment "E" group received a high subsidized rate of interest on monthly deposits while the control "C" received no such subsidies. Each group consisted of 42 individual savers. The pilot monitored amounts saved by each individual for 12 month. Participants opened their accounts during March through July of 2007 and their monthly deposits were monitored for 12 months.
a. While there are differences in reported income between the Control and Experiment groups, are these differences statistically significant?