STAT157 HW 2
Jan 24, 2022
Due Tuesday, January 31 at 11:59pm
Deliberate Practice: Cali
ation
Expected completion time: 20 minutes
Go to https:
www.openphilanthropy.org/cali
ation and complete 20 questions under the
Confidence Intervals (level 60%) category.
At the end, go to the “Results” tab and take screenshots showing that you completed at least 20
questions and your cali
ation performance (the chart that appears below the results).
Deliberate Practice: Estimation
Expected completion time: 60 minutes
For each of the following questions, estimate the answer without looking things up, then look up
the answer and calculate the relative e
or of your estimate1. For each quantity, we provided one
link with a reasonable-seeming answer, which you should use as the “official” answer when you
calculate the e
or. We recommend spending around 5 minutes on each estimation question.
In addition to the questions below, devise two estimation questions of your own, for quantities you
are interested in. Again, estimate the answer without looking things up, then look up a reasonable
answer and compute your relative e
or.
1. How many cattle are in the world in 2022?
2. What’s the length of the SF Bay Bridge, in meters?
3. How heavy, in tons, is the Titanic?
1Note that some of these questions still leave some ambiguity depending on specific definitions, and different
Google search results might give slightly different answers!
1
https:
www.openphilanthropy.org/cali
ation
4. How many paid subscribers of Netflix are there as of December 2022?
5. How many statistics and biostatistics degrees (Bachelors) were given in the U.S. in 2021?
6. What was the GDP of Mexico in 2021?
7. How many musicians are employed in the U.S.?
8. What’s the depth of the deepest hole, in meters, that humans have dug?
Here are our links that contain answers:
1. https:
www.statista.com/statistics/263979/global-cattle-population-since-1990
2. https:
en.wikipedia.org/wiki/San_Francisco%E2%80%93Oakland_Bay_Bridge
3. https:
en.wikipedia.org/wiki/Titanic
4. https:
www.demandsage.com/netflix-subscribers
5. https:
magazine.amstat.org
log/2022/12/01/statsbiostatsdegree
6. https:
countryeconomy.com/gdp/mexico
7. https:
www.zippia.com/musician-jobs/demographics
8. https:
en.wikipedia.org/wiki/Kola_Superdeep_Borehole
On Gradescope, for each of the 10 questions (8 provided plus 2 created by you), please
submit your estimate, your relative e
or, and a
ief explanation of your reasoning (e.g. what
quantities you used as part of the decomposition and how you combined them). Your explanation
can be
ief and does not have to be complete sentences. The purpose of these questions is to
get practice making estimates, rather than to get all the answers right. You will not
e graded on accuracy, but instead on whether you made a reasonable attempt and
learned from your mistakes.
La
Expected completion time: 90 minutes
Link to Jupyter notebook.
Please follow the instructions in the notebook to print out your code and answers and submit to
Gradescope. You may use languages other than Python, although we will generally be providing
starter code in Python.
2
https:
www.statista.com/statistics/263979/global-cattle-population-since-1990
https:
en.wikipedia.org/wiki/San_Francisco%E2%80%93Oakland_Bay_Bridge
https:
en.wikipedia.org/wiki/Titanic
https:
www.demandsage.com/netflix-subscribers
https:
magazine.amstat.org
log/2022/12/01/statsbiostatsdegree
https:
countryeconomy.com/gdp/mexico
https:
www.zippia.com/musician-jobs/demographics
https:
en.wikipedia.org/wiki/Kola_Superdeep_Borehole
http:
datahub.berkeley.edu/hu
user-redirect/git-pull?repo=https%3A%2F%2Fgithub.com%2Fjs-d%2Fforecasting-class-sp23&urlpath=tree%2Fforecasting-class-sp23%2Fassets%2Flabs%2Fhw2_lab.ipynb&
anch=main
Predictions
Expected completion time: 60 minutes
Register the following predictions. You can submit them by going to https:
docs.google.
com/forms/d/1He18wwYU8sha8fwbHUPUNdvNxi7LFkr2w-lxpsmbGhE/edit and following the form’s
instructions. For these predictions, (and all predictions about the future throughout this class), we
encourage you to use external sources – by googling things, reading news articles, talking to friends
who follow politics or music stats, etc.
1. Pick the same website, application, or software you chose last week, and predict how
much time you will spend on it between 12:00am Wednesday Fe
uary 1st and 11:59pm
Monday Fe
uary 7th, as measured by your time-tracking app.
2. On Fe
uary 1st at 2pm EST, the U.S. Federal Reserve (the Fed) is planning to announce
interest rates. Note that the federal interest rate is a range (e.g. 5% − 5.25%), and we will
esolve the forecast based on the upper value in the range. In terms of units, report your answer
as a percentage (e.g. 4.9 would mean a 4.9% interest rate).
3. Will Taylor Swift’s Anti-Hero top the Billboard Hot 100 on the week of Fe
uary 5th?
4. How many club tables will be there at 1PM on Upper Sproul on Fe
uary 1st? It should be any
table with the visible name of an organization, including empty tables. This question will be
esolved based on count by course staff.
For each question, submit a mean and inclusive 80% confidence interval (or a probability for question
2), as well as an explanation of your reasoning (1-2 paragraphs). Please include a copy of you
google form responses with your Gradescope submission.
3
https:
docs.google.com/forms/d/1He18wwYU8sha8fwbHUPUNdvNxi7LFkr2w-lxpsmbGhE/edit
https:
docs.google.com/forms/d/1He18wwYU8sha8fwbHUPUNdvNxi7LFkr2w-lxpsmbGhE/edit
https:
www.billboard.com/charts/hot-100/