hw08.pdf - hw08_master November 8, 2019 1 Homework 8:...

hw08_master
November 8, 2019
1 Homework 8: Confidence Intervals
Reading : * Estimation
Please complete this notebook by filling in the cells provided. Before you begin, execute the
following cell to load the provided tests. Each time you start your server, you will need to execute
this cell again to load the tests.
Homework 8 is due Thursday, 10/31 at 11:59pm . You will receive an early submission bonus
point if you turn in your final submission by Wednesday, 10/30 at 11:59pm. Start early so that
you can come to office hours if you’re stuck. Check the website for the office hours schedule. Late
work will not be accepted as per the policies of this course.
Directly sharing answers is not okay, but discussing problems with the course staff or with other
students is encouraged. Refer to the policies page to learn more about how to learn cooperatively.
For all problems that you must write our explanations and sentences for, you must provide your
answer in the designated space. Moreover, throughout this homework and all future ones, please be
sure to not re-assign variables throughout the notebook! For example, if you use max_temperature
in your answer to one question, do not reassign it later on.
[ ]: # Don't change this cell; just run it.
import numpy as np
from datascience import *
# These lines do some fancy plotting magic.
import matplotlib
% matplotlib inline
import matplotlib.pyplot as plt
plt . style . use( 'fivethirtyeight' )
import warnings
warnings . simplefilter( 'ignore' , FutureWarning )
from client.api.notebook import Notebook
ok = Notebook( 'hw08.ok' )
1

1.1 1. Plot the Vote
Four candidates are running for President of Dataland. A polling company surveys 1000 people
selected uniformly at random from among voters in Dataland, and it asks each one who they are
planning on voting for. After compiling the results, the polling company releases the following
proportions from their sample:
Candidate Proportion
Candidate C 0.47
Candidate T 0.38
Candidate J 0.08
Candidate S 0.03
Undecided 0.04
These proportions represent a uniform random sample of the population of Dataland. We will
attempt to estimate the corresponding parameters , or the proportion of the votes that each candi-
date will receive from the entire population. We will use confidence intervals to compute a range
of values that reflects the uncertainty of our estimates.
The table votes contains the results of the survey. Candidates are represented by their initials.
Undecided voters are denoted by U .
[14]: votes = Table . read_table( 'votes.csv' )
num_votes = votes . num_rows
votes
[14]: vote
C
J
C
S
J
J
T
C
T
C
… (990 rows omitted)
Question 1. Complete the function one_resampled_proportion below. It should return Candi-
date C’s proportion of votes after simulating one bootstrap sample of tbl .