Department of Economics
Professor Berman
Econometrics 120B
Winter 2022
Homework #1
Due Tuesday, Jan 18, noon (pacific time)
submit on Canvas, as pdf
1. Data gathering exercise. (Submit as a page or two with two spreadsheets, with this
question sheet.)
a. Gather data from a controlled experiment. Report the values of one variable X that you
controlled (or randomly assigned) and another Y that was influenced by X. You should have at
least 30 observations, where each observation is an (x,y) pair
which we discussed in class was an experiment in which X was price and Y was quantity
demanded. But d
report
)
Report (on this sheet) the source of the data, the sample mean of each variable, X and Y, and the
sample covariance of X and Y.
b. Gather observational data on two variables X and Y that may be related. You should have at
least 30 observations, where each observation is an (x,y) pair
are an example.)
Report (on this sheet) the source of the data, the sample mean of each variable, X and Y, and the
sample covariance of X and Y.
Notes: Conduct the experiment yourself.
Observational data could be generated on your own, but are also available on the
websites of the World Bank, the Bureau of Labor Statistics, the National Bureau of
Economic Research and the International Monetary Fund, and data.gov, to name a few.
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2. A. Define random sampling of a variable X.
Random sampling is a part of the sampling technique in which each
sample in Variable X has an equal probability of being chosen.
B. State one benefit of random sampling.
This assumption matches our initial applications to cross-sectional data, it
extends readily to panel and time series data, and because of our large-sample
approach, it poses no additional conceptual or mathematical difficulties.
3. A. Define random assignment of a variable X.
Random assignment refers to the use of chance procedures in
psychology experiments to ensure that each participant has the same
opportunity to be assigned to any given group.
B. State one benefit of random assignment.
Random assignment helps ensure that members of each group in the experiment
are the same, which means that the groups are also likely more representative of
what is present in the larger population.
C. Do random sampling and random assignment have anything in common?
If so, what?
Yes, Both of them use statistic ways to predict and come out a result. They
use two different methods though.
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