1. How many cats are in each Boston household? To investigate, we asked some randomly selected
households in Boston how many cats were present, with the following results:
5, 20, 0, 0, 7, 0, 0, 1, 2, 2, 2, 3
a.
b.
c.
d.
e.
f.
g.
h.
i.
Find the mode
Find t

1.2. a.
The ten elements are the ten cars
b.
5 variables: Size, Cylinders, City MPG, Highway MPG, and Fuel
c.
Categorical variables: Size and Fuel
Quantitative variables: Cylinders, City MPG, and Highway MPG
d.
Variable
Size
Cylinders
City MPG
Highway MPG

PELICAN STORES
Promotional Campaign Results
To Pelican Stores Management,
As a part of our most recent promotional campaign for
Pelican Stores, I have evaluated and analyzed the descriptive
statistics of net sales by customer type, percent frequency
distr

1.
A sample of 81 account balances of a credit company showed an average balance of $1,200. It is
known that the population standard deviation is $126. Suppose you want to determine whether the
mean of all account balances is significantly different from

Study Guide for EC203 Final Exam Spring 2016
1. Categorical vs. Quantitative Variables (not specifically ratio vs. interval but
nominal and ordinal vs. quantitative)
2. How to read a cross tab with row % vs column %
3. Mean (regular and weighted), Median

1.
A sample of 81 account balances of a credit company showed an average balance of
$1,200. It is known that the population standard deviation is $126. Suppose you want to
determine whether the mean of all account balances is significantly different from

Stata Assignment #1: Due 3/29 by 11:59pm
In this assignment, you will have a complete data set created by merging and appending last semesters
data. You will also create a pie chart, a bar chart a frequency table and some cross-tabs. I will walk you
throu

Stata Assignment #2 (DUE 4/28 11:59pm): Cleaning Data, Discrete
Probability Functions and Continuous Density Functions
1. Set your directory to ./Assignment #2 (Create the
folder Assignment #2 if you havent already and store
the raw data (and your log and

Midterm 2 Additional Practice Questions: EC203 Spring 2016
1. A student has to take 9 more courses before he can graduate. If none of the courses are
prerequisite to others, how many groups of four courses can he select for the next semester?
ANSWER: 126

EC203-B1, Exam 1
10/22/2015
Name:
The exam has two parts, 10 multiple choice questions (worth 2 points each) and 13 short
answer questions that are worth 90 points all together (value given on each part of those
questions). No partial credit will be given

Midterm 2 Additional Practice Questions: EC203 Spring 2016
1. A student has to take 9 more courses before he can graduate. If none of the courses are
prerequisite to others, how many groups of four courses can he select for the next semester?
2. Assume a

EC203 Problem Set 2
Solve the following problems from the book. Be aware that past editions may
have a different order.
Chapter 3:
p.117: 3.6, 3.7; p.126: 3.24 (do all the calculations by hand), 3.27, 3.29,
p.134: 3.38, 3.44; p.139: 3.46, 3.47, 3.52 (whil

Mean
3.6.
xi 657
59.73
n
11
Median = 57
Mode = 53
3.7. a.
6th item
It appears 3 times
The mean commute time is 26.9 minutes.
b.
The median commute time is 25.95 minutes.
c.
The data are bimodal. The modes are 23.4 and 24.8.
d.
The index for the third qu

1.
0, 0, 0, 0, 1, 2, 2, 2, 3, 5, 7, 20
a. Mode: 0
b. Median: 2 (since we have 12 data points, the median is the average between the two
values in positions 6th the 7th.
c. Q1 = 0, Q3 = 4. Q1 is the median of the first 6 values, Q3 is the median of the las

2. How many ways can three items be selected from a group of six items?
9. Simple random sampling uses a sample of size n from a population of size N to
obtain data that
can be used to make inferences about the characteristics of a population. Suppose tha

Summarizing Data for Two
Variables
Up to this point
Summarizing data for one variable.
Frequency distributions, including relative and percent.
Bar Chart
Pie Chart
Histogram
Dot Plot
Stem and leaf displays
What about two variables?
Crosstabulation: A tabu

Chapter 1: Data and Statistics
Statistics
Statistics is the study of collection, analysis, interpretation,
presentation and organization of data.
Applications
Finance:
Analysis and forecast of stocks prices and earning ratios.
Economics
Forecast about i

Chapter 3. Descriptive Statistics:
Numerical Measures
Chocolate Chips in Cookies
How can we quantify these differences?
Summarizing data
Want to use a couple of numbers to summarize it.
What numbers to use? (and how to obtain them?)
Summarizing Data
Answe

Chapter 3. Numerical
Summaries
Want to find the average growth rate or growth factor.
A growth factor that applied 10 times (multiplication) gives the same result
than applying all the other growth factors.
Geometric mean
Product of all the growth factor

Chapter 3: Numerical
Summaries
Last class
Median
Quartiles
Measures of dispersion
Variance
IQR
Box Plots
Skewness
A measure of how skewed is the distribution of data
Skewness
Z-Scores
The z-score of each data point is the relative location of the da

Chapter 2: Tabular and
Graphical Displays
Introduction
We want to summarize data.
Answer the following questions (among others):
What information is contained in the data?
What does the data look like?
What useful information is present in the data?
I

Chapter 4: Introduction to
Probability
Last Class:
Sample Space and Sample Points.
Counting (as a step to calculate probabilities)
From a pool of N objects, take n at a time.
Repeating allowed, order is important:
Last Class
Repeating not allowed, orde

EC 203 Empirical
Economics I
Luis Huerta
Boston University
The Bag of Candy
Objective: Accurately guess the bags weight.
Instructions:
Pick any 5 candy from the bag (sample)
Add up their individual weights
Multiply the obtained value by 20
The person/t

EC203 Problem Set 1
Solve the following problems from the book. Be aware that past editions may
have a different order.
Chapter 1:
1.2, 1.11, 1.24
Chapter 2:
2.5 (but not the pie chart), 2.10, 2.15, 2.17, 2.23, 2.27, 2.40
Case Problem 2 (page 85)
For prob

EC203-B1, Exam 1
10/22/2015
Name:
The exam has two parts, 10 multiple choice questions (worth 2 points each) and 13 short
answer questions that are worth 90 points all together (value given on each part of those
questions). No partial credit will be given