STA 9708, Baruch College, 1-31-23
Prof. L. Tatum
LN1.D
Homework Exercises
Due:
Feb
13
, 11:59 PM
Please submit your work in a Microsoft Word document, only.
Insert your Excel graph into that
Word document.
Put
your name
at the top of the first page of your homework.
Turn it in early!
An Important Alert
: when you upload a Word document to Blackboard and then take a look at on
the viewing window, your graphs may look messed up.
Remain calm, no damage has been to
your file.
The problem is with the Blackboard viewer.
When I see that problem, I simply
download the file and open it in Word.
Reading assignment
:
Lecture Note
LN1.A
.
Please try to read through Sections 1-3,
several
times, on different days
. Try to read without fear!
Look for concepts that catch your interest,
and do not spend time worrying about what to memorize for a test, as there is none.
Exercises
1. Go to the posted Stock Excel file, and find your name.
Beside your name is the ticker symbol
and name of the company assigned to you.
Assignments were made randomly, using Excel's
rand()
function.
All the companies are in the S&P500 Index.
Follow the instructions in
Section 5
, download daily data for your stock from January 1,
2006
to the January 1,
2023
.
You should have
thousands of rows
of data!
Continue on, and
compute the percentage daily return, as shown in the lecture note.
Next, construct a well-formatted time series plot of your daily returns from 2006 to the
present.
Excel instructions are given in the lecture note in
Section 4
.
You should have
thousands of data points in your graph
.
In the document you submit, do not
show any of the
data, just the graph.
2.
Review the concept of a population proportion on page 5.
Propose an
operational
definition
of the
population average
for the beverage-expenditure example.
ANSWER: In order to obtain the population average for the stated scenario, we would have ask
each individual listed on the list of approximately 168.3 million registered U.S. voters about
how much they had spent on beverages in the past 30 days.
We would then take the mean of the beverage amounts stated, i.e., add up the 168.3 million
numeric values stated (X) and divide it by 168.3 million (N).
Hence, the population average would be X/N.
3.
Review the time series plot on the third page of the lecture note, showing the net weights of
the 192 bags of Peanut M&M's.
The variation we see there is not
due to misbehavior in the
underlying system.
In the terminology of statistical process control, we would say the
variation we are seeing is due to
natural variation
, meaning variation that was
intrinsic
in the
design of that production line.
Such a production line can and will of course fall
out-of-
control
from the time-to-time, perhaps producing a shower of M&M's raining down on to the
factory floor instead of into the bags, but that is not happening here.
