CPSC 231 Tutorial Exercise 2 and Homework Assignment 2
Examining Trends of Birth Rates
(Learning Objective: understand the use of loops)
Tutorial Exercise 2
Weight: 1.25% of final grade
Submission: Nothing
Demonstrate your code to your tutorial TA. You may demonstrate as many times as you wish
until you get it right. Your TA can provide feedback each time you demonstrate.
To receive marks for the exercise, you must demonstrate to your TA before the end of your
enrolled tutorial session on either Wednesday October 12th or Thursday October 13th. Your TA
is not responsible for marking your code in an email.
Detailed Descriptions
The birth rate is one of the most basic and important measures in demography. Low birth rates
can have major impacts on the future of a society – without enough people being born, you
either have to accept huge number of immigrants to keep the economy operating, or you have
to replace the work that humans did with robots or AI.
In this exercise, you will visualize the trend of birth rates in a country.
Step 1:
Create a new py file to work on.
Step 2:
Download the new turtlesetup_plot.py file from D2L, and place it in the same directory as your
own py file.
Step 3:
Do not change anything in turtlesetup_plot.py.
Your own file should start with
from turtlesetup_plot import *
Your own file should end with
t.hideturtle()
screen.exitonclick() # No more turtle.exitonclick()
This allows you to start using the turtle in the intended way. The turtle is renamed as t to avoid
any further confusions from assignment 1. No more turtle in the code, only t. To move the turtle
forward by 100, you would use t.forward(100).
You are only allowed to import turtlesetup_plot, not any other imports. You can define your
own custom functions for this assignment, but it is not necessary. You can use anything else that
is not fo
idden in this document.
Step 4: For the tutorial exercise, your task is to plot a few points of birth rates on the graph.
The program starts by asking the user how many data points they want to enter. Assume the
user enters an integer.
The program then asks the user to enter each data point, based on the number the user
wanted. Assume Year is entered as an integer and Birth Rate is a float.
As an example:
Year Birth Rate in Canada
XXXXXXXXXX
XXXXXXXXXX
XXXXXXXXXX
See screenshot for the exact output:
And the program plots them as a line graph:
Demonstrate to your TA that you have done this work.
Homework Assignment 2
Weight: 6% of final grade
Due date: Friday October 21, at 11:59pm
Estimated time needed to complete Assignment 2: about the same as Assignment 1
Submission: one .py file, submit on the D2L Dropbox. You may submit as many times as you
wish, and only the latest submission will be marked.
Late Submissions: Submitting on October 22nd will use up one personal day. Submitting on
October 23rd will use up two personal days, etc. You have a total of 5 personal days for the
entire semester. No penalties for using personal days. An assignment will not be accepted if it is
late and all personal days are already used.
Academic Integrity: This work must be completed individually. Please follow academic integrity
ules as discussed during lecture. You may discuss your ideas in English (not in Python) with
other students as much as you like, but make sure that when you write your code that it is your
own. A good rule of thumb is to never let anyone else see your code, except your instructor and
TAs.
Detailed Descriptions
Continue working from your tutorial exercise file.
Step 1:
Let’s add some e
or checking.
• When asking the user how many data points they want to enter, assume the user enters
an integer. However, program should check to make sure this number is greater than 0.
• When asking the user to enter a year, assume the year is entered as an integer.
However, program should check to make sure the year is between 1910 and 2022
(including 1910 and 2022).
• When asking the user to enter a birth rate, assume it is a float. However, program
should check to make sure the number is between 0.2 and 4.5 (including 0.2 and 4.5).
• When asking the user to enter a year as part of the data point entry, program should
check to make sure the years have been entered in chronological order. You can’t enter
1980 before 1970, for example.
• When asking the user to enter a year as part of the data point entry, program should
check to make sure the year has not been entered before. You cannot have the same
year entered twice.
With any one of the above checks, if the user enters something that violates the rule, the
program should immediately output “E
or.” Nothing else should run (the program stops asking
for additional data points) and the program stops when the user clicks on the graph. The auto-
grader will look for this exact word with a period to determine if your program is behaving
co
ectly.
Step 2:
Let’s handle some data cleaning. If the user entered a birth rate that is more than 2 decimal
places, round the number to only 2 decimal places (e.g XXXXXXXXXXbecomes 3.44).
Step 3:
Let’s create markers. It is very difficult to see where the data points lie without clear markers.
You will draw a shape as a marker. You may use whatever shape you wish as the marker –
square, star, triangle, circle, etc.
Here is one example with little squares as markers:
You will need to draw the shape yourself – there is no code to give you an automatic marker.
Step 4:
We want to have some analysis of the data. One question to ask is, if we know the birth rate in
two separate years, can we guess what the birth rate might be in between the two years?
Year Birth Rate in Canada
XXXXXXXXXX
1964 ?
XXXXXXXXXX
XXXXXXXXXX
How do we guess what the birth rate was in 1964, given the chart above? This requires
interpolation of data. We use the line connecting the two closest points (1960, 3.81) and (1970,
2,26), and based on it, assuming a linear relationship, figure out what the birth rate might be in
1964.
After drawing the graph in step 3, add t.hideturtle() to hide the turtle if it hasn’t been done. Do
not clear the graph and do not close the graph window.
The program then asks the user to enter the two years they want to use to interpolate. Assume
the entered years are integers. Do other e
or checking as step 1 right after the user enters each
year.
If either year does not exist as an existing data point, the program should output the following
message and exit when the user clicks on the graph:
The entered data point does not exist.
The auto-grader will look for this exact sentence to determine if your program is behaving
co
ectly.
Step 5:
Based on the user entered years, the program will interpolate and produce an estimate for
every year in between the two. The birth rates should be rounded to 2 decimal places when
outputting to the screen.
The format of the output should be one data point per line: the year, one space, the birth rate
ounded to 2 decimals, end of the line (the auto-grader will use this exact format to check your
output for co
ectness.)
Do not include the years at the two ends (e.g. if between 1960 and 1970, do not include 1960
and 1970.)
Step 6: Finally, plot these estimated new data points on the graph:
Click the graph to exit the program.
• If you ever wonder how we can predict a future year birth rate, not a birth rate between
two known years – this would require machine learning (artificial intelligence).
• There are many more data points we can find on birth rates. There may be interesting
trends!
https:
datacommons.org/tools/timeline#&place=country/CAN&statsVar=FertilityRate_Person_Female
Grading
For tutorial exercise:
Grade
Point
Letter Grade Guidelines
4 A All co
ectly demonstrated to TA
3 B Mostly co
ect with minor e
ors
2 C Major e
ors
1 D Barely started code and no data points drawn
0 F Did not demonstrate to TA
For homework assignment:
Grade
Point
Letter Grade Guidelines
4 A+/A Fulfill all assignment specs, or only one mistake that is not an e
or
3.7 A- Two mistakes/one to two e
ors, or incomplete tasks
3.3 B+ Three to four mistakes/e
ors, or incomplete tasks, or code crashes on occasions
3 B Five to six mistakes/e
ors, or incomplete tasks, or code crashes on occasions
2.7 B- More than six mistakes/e
ors, or incomplete tasks, or code crashes on occasions
2.3 C+ Major mistakes/incomplete tasks and code crashes a lot
2 C Code draws some data points but crashes every time, or use other disallowed imports
1.7 C- Data points incomplete and code crashes every time
1.3 D+ Code crashes every time and nothing else is shown
1 D Code does not run due to syntax e
ors
0 F Barely started code, or no submission, or late submission with no personal days left
The assignment will be graded out of 4, with the grade based on the program’s level of
functionality and conformance to the specifications.
• If the program does not run due to syntax e
ors, it will not get more than a D grade.
• A program that runs but