Not logged in
Talk
Contributions
Create account
Log in
Navigation
Main page
About
People
Publications
Teaching
Resources
Research Blog
Wiki Functions
Recent changes
Help
Licensing
Page
Discussion
Edit
View history
Editing
Statistics and Statistical Programming (Spring 2019)/Problem Set: Week 2
(section)
From CommunityData
Jump to:
navigation
,
search
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
== Programming Challenges == :'''PC0.''' Create a new project and RMarkdown script for this week's problem set. :'''PC1.''' Run the following command (just once!) at the R console: <code> sample(x=c(1:20), size=1)</code>. The output of the command is your group number for this assignment (''Optional bonus'': Explain what this command does.). :'''PC2.''' Navigate to the [https://communitydata.cc/~ads/teaching/2019/stats/data data repository for the course] and download the RData file in the <code>week_02</code> subdirectory with your group number from PC1 associated with it (e.g., <code>group_<output>.Rdata</code>). :'''PC3.''' Load that file into R. It should contain one variable. Find that variable! :'''PC4.''' Compute and present summary statistics for your variable. Be sure to include the minimum, maximum, mean, median, variance, standard deviation, and interquartile range. <!---:'''PC5.''' Write your own functions in R to re-compute the mean and the median. Be ready to walk us through how your function works.---> :'''PC5.''' Create some visualizations of your dataset: at the very least, create a boxplot and histogram. :'''PC6.''' Some of you will have negative numbers. Whoops! Recode all negative numbers as missing (i.e. NA) in your dataset. Now compute a new mean and standard deviation. How does it change? ('''Hint:''' the <code>mean()</code> function may now produce an error. You have to include the argument <code>na.rm=TRUE</code> to work around this.) :'''PC7.''' Log transform your dataset (i.e., take the natural logarithm for each value). If you have very small values it may be helpful to add 1 to each value before you take the natural logarithm (this avoids nonsense values). Calculate the new mean, median, and standard deviation of the transformed variable. Also create a new histogram and boxplot. :'''PC8.''' Briefly discuss any important differences you observe between the original variable and the new variable (i.e., the one you removed negative values from and log-transformed). :'''PC9.''' Save your work and archive the project (i.e., in a .zip file) and [https://canvas.northwestern.edu/courses/90927/assignments/577505 upload it to canvas].
Summary:
Please note that all contributions to CommunityData are considered to be released under the Attribution-Share Alike 3.0 Unported (see
CommunityData:Copyrights
for details). If you do not want your writing to be edited mercilessly and redistributed at will, then do not submit it here.
You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource.
Do not submit copyrighted work without permission!
To protect the wiki against automated edit spam, we kindly ask you to solve the following CAPTCHA:
Cancel
Editing help
(opens in new window)
Tools
What links here
Related changes
Special pages
Page information