THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 1
The Economics of Bank Robberies in New England
Kimberly A. Leonard, Diane L. Marley & Charlotte A. Senno
The University of Rhode Island, STA308
Comment [N1]: Very good work. Points: 75 / 75
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 2
Abstract
The topic of the paper was to prove an increase in the number of bank robberies in
the six New England states of Maine, New Hampshire, Vermont, Massachusetts,
Connecticut and Rhode Island as years increased since 2003.
Seven years worth of data was collected on these six states in the areas of bank
robberies, unemployment, bankruptcy and state population.
Paired T-tests for the following pairs: 2003-2004, 2004-2005, 2005-2006, 2006-
2007, 2007-2008, 2008-2009 were calculated to determine if there was an increase in
bank robberies and unemployment. The team found no significant increase in the number
of bank robberies over the seven years; however, we found an increase in unemployment
in years 2007 – 2009.
Using a chi-square test for independence, we found that when looking at bank
robberies and bankruptcies the variables years and states are not independent and
unemployment rates were independent.
We found no relationship between unemployment rates and bank robberies using
a linear regression.
Therefore, our hypothesis of bank robberies increasing over time has been
disproved.
Introduction
Recent Rhode Island media coverage has included a large number of stories on
local bank robberies. Media focus also remains largely on the current economic
condition. But are the two issues connected?
Our hypothesis is that the frequency of bank robberies increases as economic
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 3
stability decreases. We chose to define “economic stability” as a combination of two
variables: unemployment rate and bankruptcy filings. An increase in either variable is
taken to indicate a weaker economy, whereas lower numbers are representative of more
stability.
In order to prove or disprove our hypothesis, the research team has chosen to
collect data on each of the six New England States: Connecticut, New Hampshire,
Massachusetts, Maine, Rhode Island and Vermont. For each state, the number of bank
robberies, percentage of unemployment, and number of bankruptcy filings has been
collected for a seven year period, from 2003-2009. (We planned on a ten year period, but
FBI statistics were unavailable from 2000-2002. However, this actually helps to
minimize error, as the economic condition around 9/11 would certainly be an outlier.)
The state population by year is also included for use in comparison and analysis of data.
Lit Review
Unemployment figures are drawn from the US Department of Labor (USDL)
which provides seasonally adjusted new filings and persons currently receiving benefits.
The percentages given do not include the number of persons who have exhausted their
benefits, under employed individuals, those who are no longer looking for work nor the
economic class of claimants.
According to the USDL “Seasonal adjustment is a statistical method for removing
the seasonal component of a time series used when analyzing non-seasonal trends.
Whereas, not seasonally adjusted reflects the actual current data. It is normal to report not
seasonally adjusted data for current unemployment rates. Seasonally adjusted data may
be used for the longer term comparison.”
Comment [N2]: Don’t use abbreviations
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 4
Bankruptcy is the “The legal process involved: the administration of an insolvent
debtor’s property by the court for the benefit of the debtor’s creditors. Filing by a
debtor is called voluntary bankruptcy; involuntary bankruptcy is declared by the court
upon petition by creditor (Britannica Concise Encyclopedia). We have chosen to
represent bankruptcy as a total number of filings per state, disregarding the category the
bankruptcies were filed in. Our bankruptcy data was collected from uscourts.gov.
The FBI Bank Crime Statistics electronic database lists the number of bank
robberies, bank burglaries, bank larcenies and bank extortions per year since calendar
year 2003. Definitions obtained from the US Attorneys’ Manual define these illegal
activities as: A bank robbery is the “taking or attempted taking by force, intimidation, or
extortion, of any property…in the care, custody, control, management or possession of
any bank, credit union, or savings and loan association.” Typically, some form of
violence is demonstrated. In contrast, a bank larceny is the taking of property in non-
violent face-to-face encounter and bank extortion “arises where, by telephone call or
other communication, an extortionist conveys a threat to a bank official. Where robberies
take place during an institutions working hours, burglaries include breaking and entering
when the institution in question is closed. For our data and analysis, we defined bank
robberies as an inclusive term: one value representing a combination of bank robberies,
larcenies, extortions and burglaries.
Methods
The team collected yearly data from 2003 – 2009 for the six New England states.
Data was collected in the following areas: number of bank robberies, unemployment rate
and bankruptcy filings. State population was also collected. This information is outlined
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 5
below, in both tables and graphs.
Bank Robberies
State 2003 2004 2005 2006 2007 2008 2009
CT 109 89 89 72 100 79 82
ME 11 3 12 22 2 11 9
MA 307 239 237 281 192 292 183
NH 14 26 33 23 15 19 11
RI 42 44 28 36 20 10 17
VT 3 3 7 4 4 2 10
Unemployment Rate
State 2003 2004 2005 2006 2007 2008 2009
CT 5.46 4.93 4.86 4.43 4.58 5.61 8.23
ME 5.03 4.63 4.88 4.67 4.67 5.36 8.03
MA 5.81 5.22 4.84 4.76 4.43 5.3 8.42
NH 4.46 3.88 6.33 3.54 3.53 3.92 6.32
RI 5.42 5.24 5.08 5.03 5.3 7.65 11.21
VT 4.46 3.71 3.52 3.73 3.93 4.53 6.88
Bankruptcy Filings
State 2003 2004 2005 2006 2007 2008 2009
CT 12,246 11,423 15,272 5025 5890 8229 10334
ME 4660 4508 6614 1323 2304 3033 3871
MA 18260 18444 26714 8400 13705 16538 20966
NH 4426 4651 6097 1925 2983 3931 5233
RI 4557 4142 5839 1621 2817 4300 5096
VT 1903 1698 2622 655 895 1275 1559
U.S. Census State Pop
State 2003 2004 2005 2006 2007 2008 2009
CT 3467673 3474610 3477416 3485162 3488633 3502932 3518288
ME 1303102 1308253 1311631 1314963 1317308 1319691 1318301
MA 6451637 6451279 6453031 6466399 6499275 6543595 6593587
NH 1281871 1292766 1301415 1311894 1317343 1321872 1324575
RI 1071504 1071414 1064989 1060196 1055009 1053502 1053209
VT 616559 618145 618814 619985 620460 621049 621760
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 6
0
1000000
2000000
3000000
4000000
5000000
6000000
7000000
1 2 3 4 5
Po
pu
lati
on
Year
New England State Populations, 2003-2009
CT
ME
MA
NH
RI
VT
0
50
100
150
200
250
300
350
1 2 3 4 5
Ba
nk
Ro
bb
eri
es
Year
N.E. Bank Robberies, 2003-2009
CT
ME
MA
NH
RI
VT
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 7
Mean, Median, Mode Summary statistics: Bank Robberies
0
10,000
20,000
30,000
1 2 3 4 5
# o
f F
ilin
gs
Year
Bankruptcy Filings, 2003-2009
CT
ME
MA
NH
RI
0
5
10
15
1 2 3 4 5
Pe
rce
nt
Un
em
plo
ym
en
t (%
)
Year
Unemployment Rates, 2003-2009
CT
ME
MA
NH
RI
VT
Column n Std. Dev. Std. Err. Median Range Min Max Q1 Q3 Mean
2003 6 117.34905 47.90755 28 304 3 307 11 109 81
2007 6 76.19383 31.106 17.5 190 2 192 4 100 55.5
2004 6 89.96592 36.72843 35 236 3 239 3 89 67.333336
2005 6 87.95832 35.908836 30.5 230 7 237 12 89 67.666664
2006 6 104.39923 42.620808 29.5 277 4 281 22 72 73
2008 6 112.83868 46.066196 15 290 2 292 10 79 68.833336
2009 6 70.11419 28.623999 14 174 9 183 10 82 52 Comment [N3]: When presenting your data always use the same number of decimal points in a column. Unless the numbers are very small a two or three decimal accuracy should be enough
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 8
Summary statistics: Unemployment Rates
Summary statistics: Bankruptcy Filings
Summary statistics: State Population
Column n Mean Std. Dev. Std. Err. Median Range Min Max Q1 Q3
2003 6 5.1066666 0.5585577 0.22803022 5.225 1.35 4.46 5.81 4.46 5.46
2004 6 4.6016665 0.6654748 0.27167892 4.78 1.53 3.71 5.24 3.88 5.22
2005 6 4.9183335 0.8927803 0.36447603 4.87 2.81 3.52 6.33 4.84 5.08
2006 6 4.36 0.5965233 0.2435296 4.55 1.49 3.54 5.03 3.73 4.76
2007 6 4.4066668 0.615424 0.2512458 4.505 1.77 3.53 5.3 3.93 4.67
2008 6 5.395 1.270067 0.51850265 5.33 3.73 3.92 7.65 4.53 5.61
2009 6 8.181666 1.6978271 0.69313496 8.13 4.89 6.32 11.21 6.88 8.42
Column n Mean Std. Dev. Std. Err. Median Range Min Max Q1 Q3
2003 6 7675.3335 6254.9243 2553.5623 4608.5 16357 1903 18260 4426 12246
2004 6 7477.6665 6279.591 2563.6323 4579.5 16746 1698 18444 4142 11423
2005 6 10526.333 8988.18 3669.4087 6355.5 24092 2622 26714 5839 15272
2006 6 3158.1667 2982.5876 1217.6364 1773 7745 655 8400 1323 5025
2007 6 4765.6665 4673.1763 1907.8162 2900 12810 895 13705 2304 5890
2008 6 6217.6665 5550.371 2265.9294 4115.5 15263 1275 16538 3033 8229
2009 6 7843.1665 7043.32 2875.423 5164.5 19407 1559 20966 3871 10334
Column n Mean Std. Dev. Std. Err. Median Range Min Max Q1 Q3
2003 6 2365391 2233717.2 911911.25 1292486.5 5835078 616559 6451637 1071504 3467673
2004 6 2369411.2 2232490 911410.25 1300509.5 5833134 618145 6451279 1071414 3474610
2005 6 2371216 2232900.8 911577.94 1306523 5834217 618814 6453031 1064989 3477416
2006 6 2376433.2 2237617.2 913503.4 1313428.5 5846414 619985 6466399 1060196 3485162
2009 6 2404953.2 2286446.5 933437.9 1321438 5971827 621760 6593587 1053209 3518288
2007 6 2383004.8 2249781.2 918469.3 1317325.5 5878815 620460 6499275 1055009 3488633
2008 6 2393773.5 2266837.2 925432.44 1320781.5 5922546 621049 6543595 1053502 3502932
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 9
Population is consistent for each state over the seven year period. The shape is
fairly consistent with unemployment with the exception of New Hampshire in fiscal year
2005. Bankruptcy filings have a consistent shape for all states; however, Massachusetts
and Connecticut have significantly higher rates. The number of bank robberies reflects a
relatively similar shape with outliers in Massachusetts and Connecticut shows elevated
rates.
Comment [N4]: Label your graphs / charts and then refer to them when analyzing.
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 10
The median in the bank robbery box plot is relatively the same throughout and the
IQR which represents 50% of the data is also stable across the years. The outliers are
from the bank robberies committed in Massachusetts as seen on the line graphs. The
median in the box plot reflecting bankruptcy filings are consistent except in 2005 and
2006. Further research shows that a change in bankruptcy laws which made filing for
bankruptcy more difficult drove the number of filings up in 2005 followed by a much
lower amount in 2006, once the law went into effect. This also resulted in the drastic
lowering of the IQR in 2006, which remained fairly low for the rest of the years we
observed.
Analysis & Results
Paired T Test
Hypothesis test results: Bank Robberies
μ1 - μ2 : mean of the paired difference between 2003 and 2004
H0 : μ1 - μ2 = 0
HA : μ1 - μ2 < 0
Tcv = -2.015
DO NOT REJECT
Hypothesis test results: Bank Robberies
μ1 - μ2 : mean of the paired difference between 2004 and 2005
H0 : μ1 - μ2 = 0
HA : μ1 - μ2 < 0
DO NOT REJECT
Difference Sample Diff. Std. Err. DF T-Stat P-value
2003 - 2004 13.666667 11.712292 5 1.1668652 0.8521
Difference Sample Diff. Std. Err. DF T-Stat P-value
2004 - 2005 -0.33333334 3.6757464 5 -0.09068453 0.4656
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 11
Hypothesis test results: Bank Robberies
μ1 - μ2 : mean of the paired difference between 2005 and 2006
H0 : μ1 - μ2 = 0
HA : μ1 - μ2 < 0
DO NOT REJECT
Hypothesis test results: Bank Robberies
μ1 - μ2 : mean of the paired difference between 2006 and 2007
H0 : μ1 - μ2 = 0
HA : μ1 - μ2 < 0
DO NOT REJECT
Hypothesis test results: Bank Robberies
μ1 - μ2 : mean of the paired difference between 2007 and 2008
H0 : μ1 - μ2 = 0
HA : μ1 - μ2 < 0
DO NOT REJECT
Hypothesis test results: Bank Robberies
μ1 - μ2 : mean of the paired difference between 2008 and 2009
H0 : μ1 - μ2 = 0
HA : μ1 - μ2 < 0
DO NOT REJECT
The team performed a series of paired T-tests for the data collected on
number of bank robberies. Each hypothesis test resulted in a “DO NOT REJECT.”
This means we cannot reject the null (that bankruptcies do not change between
each 2 year period). There could be some change, but we did not have sufficient
evidence to prove bank robberies increased over time.
Difference Sample Diff. Std. Err. DF T-Stat P-value
2005 - 2006 -5.3333335 8.807825 5 -0.6055222 0.2856
Difference Sample Diff. Std. Err. DF T-Stat P-value
2006 - 2007 17.5 15.903354 5 1.1003969 0.8394
Difference Sample Diff. Std. Err. DF T-Stat P-value
2007 - 2008 -13.333333 17.865547 5 -0.7463154 0.2445
Difference Sample Diff. Std. Err. DF T-Stat P-value
2008 - 2009 16.833334 18.59286 5 0.90536547 0.7966
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 12
Hypothesis test results: Unemployment Rates
μ1 - μ2 : mean of the paired difference between 2003 and 2004
H0 : μ1 - μ2 = 0
HA : μ1 - μ2 < 0
Tcv = -2.015
DO NOT REJECT
Hypothesis test results: Unemployment Rates
μ1 - μ2 : mean of the paired difference between 2004 and 2005
H0 : μ1 - μ2 = 0
HA : μ1 - μ2 < 0
DO NOT REJECT
Hypothesis test results: Unemployment Rates
μ1 - μ2 : mean of the paired difference between 2005 and 2006
H0 : μ1 - μ2 = 0
HA : μ1 - μ2 < 0
DO NOT REJECT
Hypothesis test results: Unemployment Rates
μ1 - μ2 : mean of the paired difference between 2006 and 2007
H0 : μ1 - μ2 = 0
HA : μ1 - μ2 < 0
DO NOT REJECT
Difference Sample Diff. Std. Err. DF T-Stat P-value
2003 - 2004 0.505 0.07961365 5 6.3431334 0.9993
Difference Sample Diff. Std. Err. DF T-Stat P-value
2004 - 2005 -0.31666666 0.4349074 5 -0.7281244 0.2496
Difference Sample Diff. Std. Err. DF T-Stat P-value
2005 - 2006 0.55833334 0.45444778 5 1.2285974 0.8631
Difference Sample Diff. Std. Err. DF T-Stat P-value
2006 - 2007 -0.046666667 0.08781293 5 -0.53143275 0.3089
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 13
Hypothesis test results: Unemployment Rates
μ1 - μ2 : mean of the paired difference between 2007 and 2008
H0 : μ1 - μ2 = 0
HA : μ1 - μ2 < 0
REJECT
Hypothesis test results: Unemployment Rates
μ1 - μ2 : mean of the paired difference between 2008 and 2009
H0 : μ1 - μ2 = 0
HA : μ1 - μ2 < 0
REJECT
The team performed a series of paired T-tests for the data collected on
unemployment rates, as well. The hypothesis test could not be rejected for intervals
from 2003 to 2007. This means there was not sufficient evidence to prove that
unemployment rates changed over this time. From 2007-2008 and 2008-2009,
hypothesis tests resulted in rejecting the hypothesis. This means unemployment
rates probably did change during these 2 year periods, but we cannot determine if
they increased or decreased, as we performed a one sided test. This is most likely
because of NH, as you can see in the unemployment graph; NH’s unemployment
varies from the normal distribution from 2007 to 2009.
Contingency table results: Bank Robberies
CRITICAL VALUE: 43.7773
REJECT
Difference Sample Diff. Std. Err. DF T-Stat P-value
2007 - 2008 -0.98833334 0.28680328 5 -3.4460323 0.0092
Difference Sample Diff. Std. Err. DF T-Stat P-value
2008 - 2009 -2.7866666 0.19067715 5 -14.61458 <0.0001
Statistic DF Value P-value
Chi-square 30 106.38439 <0.0001
Comment [N5]: A one-sided test would tell you if it increased or decreased. In your case since you are assuming U1 - U2 < 0 it implies that U1 is less than U2. A rejection of the null implies that U1 is less than U2. However, I doubt if the program you used to do the test actually did a one sided test. So unless you compared to the CV your self it was a two-sided test and your alternative hypothesis should have been stated as a two-sided test – U1 – U2 <> 0
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 14
Contingency table results: Unemployment Rates
DO NOT REJECT
Contingency table results: Bankruptcy Filings
REJECT
Chi-square analyses for bank robberies, unemployment and bankruptcy filings,
were conducted to determine if these values were independent of year and state. For
bank robberies and bankruptcy, the chi-square test result was to reject the null. This
means these values are not independent of year and state. In contrast, unemployment
rates were independent of year and state.
Simple linear regression results: Dependent Variable: Bank Robberies
Independent Variable: Unemployment %
Bank Robberies = 44.650345 + 4.1325645 Unemployment %
Sample size: 42
R (correlation coefficient) = 0.0719
R-sq = 0.0051705735
Estimate of error standard deviation: 89.67284
Parameter estimates:
Analysis of variance table for regression model:
Statistic DF Value P-value
Chi-square 30 2.7876186 1
Statistic DF Value P-value
Chi-square 30 1715.481 <0.0001
Parameter Estimate Std. Err. Alternative DF T-Stat P-Value
Intercept 44.650345 49.827812 ≠ 0 40 0.8960929 0.3756
Slope 4.1325645 9.063472 ≠ 0 40 0.45595822 0.6509
Source DF SS MS F-stat P-value
Model 1 1671.7522 1671.7522 0.20789789 0.6509
Error 40 321648.72 8041.2183
Total 41 323320.47
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 15
H0: B = 0
Ha: B ≠ 0
The linear regression test resulted in a P value of 0.6509 therefore the null
hypothesis is not rejected. Our findings reflect that there is no relationship between
unemployment and bank robberies.
Discussion/Conclusion
The point of this research was to determine if there is a relationship between the
number of bank robberies and the economic factors of unemployment rates and
bankruptcy filings. Our hypothesis was that increased unemployment and bankruptcy
would result in increased prevalence of bank robberies. We believe the recent economy
has declined and the number of bank robberies reported in the media has increased.
The paired-T test disproved an upward trend in bank robberies. There was no
significance in unemployment, either, until 2007, where it remained significant in 2 year
periods until 2009. This is consistent with our observation of increased unemployment in
recent years.
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 16
Our linear regression test tested for correlation between unemployment rates and
number of bank robberies. After performing the test, we determined there is no
correlation between these two variables based on the evidence presented.
Therefore, all of our testing has proven our initial hypothesis was incorrect---there
is no notable relationship between bank robberies and unemployment/bankruptcy based
on the data we collected and analyzed.
THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 17
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THE ECONOMICS OF BANK ROBBERIES IN NEW ENGLAND 18
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