Stat 100: Quantitative Methods Homework 3
Due Sunday, July 13
0
Homework policy: This homework is due by 5:00pm eastern standard time on the
due date. Homework is to be handed in to the gmail address of your assigned TF.
Late homework will not be accepted
Stat 100: Quantitative Methods for Economics
Homework 1: Due Monday, June30
Homework policy: Homework is due by 11:59pm eastern standard time on the due date.
Homework is to be handed in to the gmail address of your assigned TF. Late homework
will not be
STATISTICS 100
MIDTERM PRACTICE PROBLEM SOLUTIONS
PAGE 1 OF 14
Statistics 100
Midterm Practice Problems
Solutions
1. (26 points total) Suppose that in 2004, the verbal portion of the Scholastic Aptitude Test
(SAT) had a mean score of = 500 and a standard
Initials:
Statistics 100 Spring 2010 Midterm Examination
Solutions Monday, 8 March 2010
Name:
Section TF/day and time:
Put your name on the rst page and your initials at the top of each page.
This is an open book, open notes exam. You may refer to your
Statistics 100 Midterm
Spring 2011
9 March 2011
Solutions
1. Short answer questions.
(a) A and B are not disjoint. Pr(B |A) = Pr(B ) implies A and B are independent,
so Pr(A and B ) = Pr(A) Pr(B ) > 0. If A and B were disjoint, Pr(A and B ) = 0.
(b) Solve
Statistics 100 Spring, 2012 Problem Set 3
Solutions
1. a)
We could dene most people to be the middle 95% of people. Then an interval containing most peoples
body temperature would be (tlow , thigh ) where
P (tlow < T < thigh ) = 0.95
By symmetry
P (T < th
Statistics 100 Spring 2012 Problem Set 5
Solutions
1. IPS 4.28
(a) How can we verify a legitimate assignment of probabilities? By showing that they sum to 1 (and
note they are all between zero and one): 0.000+0.036+0.003+0.121+.060+0.691+0.062+0.027 = 1
(
Name:
Assigned TF and Section time:
Statistics 100 Quiz 1
Wednesday 9 February 2011
This quiz has three questions and is worth 25 points; two of the questions are on the second
page.
.3
The histogram below shows the distribution of the carbohydrates (meas
Name:
Statistics 100 Quiz 1
Wednesday 3 February 2010
The histogram below shows the distribution of infant mortality rates (deaths per 1,000 live
births) in a selection of countries around the world.
0
10
Percent
20
30
40
ytilatrom00ni
ytilatrom00ni
tnecr
1)
tstat = (5.23 - 5.50) /(0.24/SQRT(64) = -9.0 < -1.64
We reject the null hypothesis. The bags of popcorn weigh less than 5.5 ounces on an average.
2)
tstat = (7.8 8.0)/(0.5/SQRT(50) = -2.82
Therefore tstat < -1.96 and hence we reject the null hypothesis
1)
(a)
. regress
Time SquareFeet Rooms Bathrooms Crew Children Frequency
Source
SS
df
MS
Model
Residual
28274.9872
17605.3557
6
63
4712.49787
279.45009
Total
45880.3429
69
Number of obs
F( 6,
63)
Prob > F
R-squared
Adj R-squared
Root MSE
664.932505
Time
C
Statistics 100 Midterm
Spring 2012
7 March 2012
Solutions
1. Short answer questions.
(a) IQR = 106 96 = 10; (1.5)(IQR) = 15, so the lower outlier boundary is
96 15 = 81. 82 is inside the boundary and is not an outlier.
(b) Using the tables of the standard
Statistics 100 Spring, 2012 Problem Set 2
Solutions
1. Standard Normal Distribution
(a) From the table in the front of the book, we see that the area to the left of 2.60 in the normal
distribution is 0.9953, so we expect the probabilty that z is greater t
Statistics 100 Spring, 2012 Problem Set 1
Solutions
1. Stata Mini-Tutorial
(a) The data probably does not only include police records because police records do not include all
violent crime, some crime is not even reported to the police. There are other s
Name:
Assigned TF and Section time:
Statistics 100 Quiz 1
Wednesday 8 February 2012
This quiz has three questions and is worth 25 points; two of the questions are on the second
page.
.15
The histogram below shows the distribution of the average age at rst
Statistics 100 Quiz 2
Solutions
Wednesday 17 February 2010
A slightly anxious couple has one child (a boy) and is worried that the child may not be eating
properly, perhaps causing it to grow more slowly than would be expected. The child is 12 months
old
Name:
Assigned TF and Section time:
Statistics 100 Quiz 2
Wednesday 22 February 2012
This quiz has four questions and is worth 25 points; two of the questions are on the second
page.
10
12
The scatterplot below shows infant mortality (deaths in the rst ye
Name:
Assigned TF and Section time:
Statistics 100 Quiz 2
Wednesday 23 February 2011
This quiz has ve questions and is worth 25 points; four of the questions are on the second
page.
300
400
Distance
500
600
The scatterplot below shows the relationship bet
Statistics 100 Quiz 3
Wednesday 3 March 2010
Name:
Section TF/day and time:
The fertility rate in a country is the total births per woman between age 15 and 49. By using
data from many countries around the world, a public health study examined the relatio
Name:
Assigned TF and Section time:
Statistics 100 Quiz 3
Wednesday 23 March 2011
At the Dana-Farber Cancer Institute all faculty and staff must take a tuberculosis (TB) test
every year. A positive test result suggests that someone has the disease, and a
Name:
Assigned TF and Section time:
Statistics 100 Quiz 4
Wednesday 6 April 2011
There are three problems on the quiz. The third problem is on the back page.
Suppose home prices in a city are approximately Normally distributed with a standard
deviation of
Statistics 100 Quiz 4
Wednesday 31 March 2010
Name:
Section TF/day and time:
Suppose that Harvard admits 2050 students for each Septembers freshman class and that
there is an 80% chance that an admitted student will decide to accept the oer to attend Harv
Statistics 100 Quiz 5
Wednesday 14 April 2010
Name:
Section TF/day and time:
Resting Energy Expenditure (REE) in cystic brosis
An investigator wishes to study whether patients with cystic brosis (CF) use a dierent
amount of energy at rest than healthy ind
Name:
Assigned TF and Section time:
Statistics 100 Quiz 5
Wednesday 20 April 2011
(25 total points) There are three problems on this quiz; the third is on the back page.
Is the gestational age (time between conception and birth) of a low birth-weight baby
Statistics 100 Quiz 6
Wednesday 21 April 2010
Solutions
This problem comes from the 2009 nal exam. The table below shows the result of a multiple
regression using 1990 data from each of the 50 US states. The response variable is the percent of
families th