The document discusses various statistical concepts and calculations related to data such as random sampling, exercise effects on memory, percentiles, and box plots. It also presents a study on the relationship between legalized abortion and declining crime rates in the U.S., suggesting that the reduction in the number of children born, who could have been at risk of criminal behavior, contributed to this decline. The author highlights the controversial implications of the findings and their potential influence on public opinion regarding abortion.

1. 1. A random sample is one ______
a. That is haphazard
b. That is unplanned
c. In which every unit of a particular size has an equal
probability of being selected
d. That ensures that there will be no uncertainty in the
conclusions
2. The following distribution has:
a. A positive skew
b. A left skew
c. No skew
d. A negative skew
3. In an experiment on the effect of exercise on memory, the
independent variable is: _____(choose only one answer)
a. Number of hours of exercise
b. Recall score on a memory test
c. Gender of the subjects
d. Gender of the experimenter
4. For the scores 3, 5, 8, 10, 14, 17, 21, 25, calculate the 75th
percentile using the following formula: R = P/100 x (N + 1)
a. 6.75
b. 17
c. 21
d. 20
5. For the following data COMPUTE THE (ƩX)2 AND THE

2. ƩY2
X
Y
1
3
2
2
4
7
a. 21 AND 62
b. 49 AND 144
c. 49 AND 62
d. 21 AND 144
6. How many 78s are there in the dataset is (multiply stems by
10.0):
a. 0
b. 1
c. 3
d. 7
7. Stem and leaf displays are NOT good for comparing two
groups.
a. True
b. False
8. Although bar charts are often used to show means, what is
typically a better display
a. Stem and leaf plots
b. Box plots

3. c. Histograms
d. Frequency tables
9. Based on the frequency polygon of test scores displayed
below, _____.
a. Nobody scored below a 55
b. Nobody scored a 0
c. The most common score was a 75
d. Everyone got a perfect score
10. Response times were generally shorter to the:
a. Large target
b. Small target
11. This bar chart shows percent increase in consumer price
index for four, three-month periods ending the date shown, In
which quarter did the CPI increase SECOND-MOST?
a. the quarter ending July 2000
b. the quarter ending October 2000
c. the quarter ending January 2001
d. the quarter endinig April 2001
12. For the following histogram of test scores,the majority of
test scores came between:
a. 39.5 and 49.5
b. 89.5 and 99.5
c. 79.5 and 89.5
d. 159.5 and 169.5

4. 13. For the following line graph of quarterly percentage
changes in five components of the CPI, which component
steadily increased from quarter to quarter?
a. Housing
b. Medical Care
c. Food and Beverage
d. Recreation
e. Transportation
14. For the following stem and leaf plot, how many numbers
are there between -2 and -1?
4|33
3|56
2|00456
1|00134
0|1245589
-0|0679
-1|005559
-2|7
a. 0
b. 1
c. 5
d. 7
15. For the following box plot, F represents:
a. The mode
b. The mean
c. The median
d. A far out value

5. 16. A researcher collected BMI (Body Mass Index) of 10
students trained to become dietitians. The BMI for the ten
students are: 18.4, 19.0, 21.4, 25.0, 23.5, 48.6, 23.6, 24.0,
18.1, 26.0
The researcher wants to know the MEAN AND THE MEDIAN
BMI score (CALCULATE 2 NUMBERS):
17. (SAME DATA SET) The researcher wants to know the
MINIMUM, MAXIMUM AND RANGE of BMI scores
(DETERMINE 3 NUMBERS):
18. (SAME DATA SET) The researcher wants to know the
VARIANCE AND STANDARD DEVIATION of BMI scores
(CALCULATE 2 NUMBERS):
19. (SAME DATA SET) The researcher wants to know the
interquartile range of BMI scores: (hint: 25% of the BMI scores
is 19) (CALCULATE 1 NUMBER)
20. (SAME DATA SET) The researcher wants to know the
OUTLIER of the BMI scores (DETERMINE 1 NUMBER)
1
BY ROBERT J. BARRO
DOES ABORTION LOWER
THE CRIME RATE?
C
rime in the U.S. has fallen dramati- can also explain why the

6. national crime rate
cally since 1991. By 1998, the homi- continued to fall through
1998 and is project-
cide rate was down by more than one- ed to keep falling for a
further 10 to 20 years.
third, and the rates for all violent crime and In fact, the authors
estimate that the number
property crime were each down by around of abortions and the
consequent reduction in
one-quarter. crime would have been significantly greater
Many explanations have been offered for had not the 1976 Hyde
Amendment, which re-
the decline, including increased expenditures stricted federal
funding of abortions through
on prisons and police, better policing strate- Medicaid, been in
effect in various forms.
gies, the strong U.S. economy, and the di- Second, a few states,
including New York
minished role of crack cocaine. Spending on and California,
legalized abortion by 1970,
prisons and police has been increasing since three years before
the U. S. Supreme Court’s
the 1970s however, so this factor therefore Roe vs. Wade
decision in 1973. As the theory
does not explain why crime rose until 1991 implies, the early
legalizers experienced falling
and then fell sharply. Better policing methods, crime rates
sooner than the rest of the coun-
as promoted by Mayor Rudolph W. Giuliani in try. Finally,
abortion rates responded to the
New York, may be making a difference. But legalization
differently across states, and those
EXPLOSIVE:

7. crime rates also fell substantially in Los An- with the highest
rates of abortion in the 1970s
geles and the District of Columbia, which are experienced the
sharpest drops in crime in
A new study
not renowned for their policing skills. As to the 1990s.
the strong economy, it is hard to show gen- WEEDED OUT. The
researchers estimate that,
erally that growth in income and employment for every 1,000
extra abortions in 1973 to
contends that leads to less crime. For example, the economy
1976, there were 380 fewer property crimes,
falling crime
performed well from 1983 to 1989, while na- 50 fewer violent
crimes, and 0.6 fewer mur-
tional crime rates rose. Finally, the fall in ders in 1997. Overall,
the abortion effect ac-
crime rates after 1991 occurred in places counted for one-half
of the drop in crime from
in the 1990s is a factor.where crack cocaine had never been
much of 1991 to 1997. The rest is explained by in-creases in
prisons, police, and other factors, or
due to the rise A recent study, “Legalized Abortion and goes
unexplained.Crime,” by Professors John Donohue of the About
20% of the abortion-related drop in
in abortions Stanford University Law School and Steven crime
arose because of the reduced populationLevitt of the University
of Chicago, proposes of 15-to-24-year-olds (the high-crime age
after Roe vs. a new causal factor: the legalization of abor-
group) in the 1990s. The main effect, however,tion in the early
1970s. The idea is that the is the reduced frequency of crime
among

8. Wade children who were not born would have been those in the
15-to-24 age group who did man-disproportionately likely to
grow up in pover- age to be born and grow up. Apparently,
ty and on welfare with a young and poorly abortion particularly
weeded out the children
educated single parent. Because these fac- who would have been
likely to follow criminal
tors are known to breed crime, the children careers.
not born would have been prime candidates to Donohue and
Levitt argue reasonably that
be criminals 15 to 25 years later. Hence, the they are carrying
out objective scientific re-
absence of these children contributes to the search about the
determinants of crime and
drop in crime rates since 1991. My reactions that the policy
implications can be left to oth-
to this idea: (1) This is a surprising hypothe- ers. The effect on
crime, even if confirmed by
sis. (2) It may well be correct. (3) The impli- further study,
would probably not moderate
cations are explosive politically and are likely the views of pro-
lifers, who view abortion as
to cause a major ruckus. murder. Similarly, the evidence would
have lit-
TIMING Donohue and Levitt present three tle influence on pro-
choice advocates, who al-
types of evidence to support their theory. ready view a
woman’s right to an abortion as
First, the sharp rise in legal abortions-from a fundamental
liberty. But for people with
fewer than 750,000 in 1973 to a plateau of less extreme views,
including me, the policy
around 1.5 million a year since the early implications could be
important. If abortion

9. Robert J. Barro is a professor of eco- 1980s-fits with the timing
of the drop in na- rights turn out to be a strong crime fighter,
nomics at Harvard University and a tional crime rates since
1991. The cumulative
senior fellow of the Hoover lnstitution
then opinion is likely to move in favor of
([email protected]). effect from abortions 15 to 25 years earlier
these rights.
30 BUSINESS WEEK / SEPTEMBER 27. 1999