Announcements
- June 7. Using R to perform the paired-sample t-test: suppose that you have two data vectors
g1 and g2 representing data for two groups 1 and 2:
> g1 [1] 111 75 106 109 85 > g2 [1] 105 119 77 133 110
There are two ways to perform the paired two-sample t-test. For Project 5, use Method 1 for Problem 3c; use Method 2 for Problem 5a.
Method 1:
> t.test(g1, g2, paired=TRUE) Paired t-test data: g1 and g2 t = -0.89747, df = 4, p-value = 0.4202 alternative hypothesis: true mean difference is not equal to 0 95 percent confidence interval: -47.48602 24.28602 sample estimates: mean difference -11.6
Method 2:
> diff <- g1 - g2 > print(diff) [1] 6 -44 29 -24 -25 > t.test(diff, mu=0) One Sample t-test data: diff t = -0.89747, df = 4, p-value = 0.4202 alternative hypothesis: true mean is not equal to 0 95 percent confidence interval: -47.48602 24.28602 sample estimates: mean of x -11.6 - June 5. Final exam review materals are posted on the Exam Info Index Page. We will discuss these items today.
- June 4. Practice Quiz 7a is posted. It will close on Tuesday, June 11.
- May 29. The due date for Project 4 has been changed to June 2.
- May 26. Practice Quiz 6a is posted. It closes on Sunday, June 2.
- May 20. Signup for the proctored final exam is open. Slots to take the proctored final will fill up, so please sign up as soon as possible to obtain the time slot that you want.
- May 18. The dropbox for Project 3 is posted on D2L. This project will not be counted late if submitted by Monday, May 20.
- May 10. The scores for the midterm are posted on D2L.
- May 10. The due date for Project 3 is May 17.
- May 6. Scaled midterm scores will be posted before or on Saturday, May 11.
- Apr 23. The questions and answers for the closed practice quizzes are posted. These are Practice Quizzes 1a, 2a, and 2b. See the Quizzes link on the left.
- Apr 22. Reminder: if you are in the async section, sign up for the proctored midterm if you have not done so already.
- Apr 15. For Practice Quiz 2a, the answer was scored incorrectly by D2L. For those that already took this quiz, I manually corrected your score. For those that must still take this quiz, it should be correctly graded from now on.
- Apr 14. The due date of Project 2a is April 19.
- Apr 14. Reminder: Practice Quiz 1a closes tonight at midnight. Please complete your attempts for this quiz by then.
- Apr 13. Practice Quiz 2b is posted. Please complete your attempts for this quiz by Sunday, April 21. Practice quizzes cannot be taken late.
- Apr 7. Even though the solar eclipse is occuring tomorrow, we will have class as usual.
- Apr 7. This annoucement is to clear up some misleading information from last week:
- Although histograms for most statistical packages (e.g., SPSS, SAS, Minitab) are left inclusive
(the intervals look like this [a, b)), the default for R histograms is to be right inclusive with
intervals like this: (a, b]. You can make the histogram
left inclusive by setting the right argument:
> hist(v, right=FALSE)
The fact that R is right inclusive may be because R was written in New Zealand. - For a boxplot, it is common for an extreme outliers to be plotted with a * and mild outliers to be plotted with an o. However, the R boxplot function plots all outliers with the symbol o.
- Although histograms for most statistical packages (e.g., SPSS, SAS, Minitab) are left inclusive
(the intervals look like this [a, b)), the default for R histograms is to be right inclusive with
intervals like this: (a, b]. You can make the histogram
left inclusive by setting the right argument:
- Apr 6. Here is a better way of saving graphical output in a Word file than saving it as a metafile.
Run the R function that produces graphical output, for example,
> hist(exam_scores)
Then right click in the graphical output window, select Copy as bitmap, then paste the graph into your Word file with Control-V. This provides a graph that will resize better than saving it as a metafile. - Apr 4. Practice Quiz 1a is posted. You can have up to three attempts; each attempt has a time limit of 60 minutes. Please complete your attempts by Sunday night, April 14. Quizzes cannot be taken late.
- Apr 4. The Attendance Verification dropbox is posted. If you did not attend class in person last Monday or Wednesday, and did not submit Project 1, submit a document to this dropbox stating that you wish to remain in the class. If you do not wish to remain in IT 223, please drop by Sunday, April 14.
- Apr 3. Each quarter, the university asks instructors to submit a no-show list for the classes that they teach. You can get off of the no-show list in four ways (1) attending class in person on April 1 or 3, (2) submitting Project 1, (3) submitting your study log for Week 1, (4) submitting a document to the AttendanceVerification dropbox stating that you wish to remain in the class. Please do at least one of these things by Monday noon, April 8.
- Apr 3. See Announcement Apr 1f for details about study logs for obtaining credit for attendance.
- Apr 2. If you can't access the COL class recordings on the IT 223 Homepage, try this link:
courseonline.cdm.depaul.edu/Play/GetCourseList.aspx - Apr 1a. The first meeting of the IT 223 class for Spring is in Room CDM 216 on April 1 at 1:30pm.
- Apr 1b. Office hours are 11:00am to 12:30pm on Mondays and Friday -- they can be in person, by phone, or via Zoom.
- Apr 1c. All course materials will be posted on this website. D2L will only be used for (1) submitting projects, (2) posting course scores and comments, and (3) practice quizzes.
- Apr 1d. Practice quizzes count 10% of your course score. You can take each practice quiz up to 3 times. The highest score that you obtain will be used for your quiz score. Quizzes taken on Monday will be due on Thursday, 10 days later. Practice Quizzes taken on Wednesday will be due on Sunday, 11 days later. Practice Quizzes cannot be taken late.
- Apr 1e. The first quiz, Practice Quiz 1a, will open on Wednesday, April 3.
- Apr 1f. Attendance counts 10% of your grade. Students that are in the async section will
obtain credit for attendance by submitting study logs, which will summarize what you did
to study for IT 223 during the preceding week. Although exactly what you submit is up to
you, here are some suggestions: the number of hours you spent studying for the various
parts of the class (e.g., watching lectures and studying class examples, working on
tutorials, projects, and practice quizzes), what did you find interesting, hard, or
confusing, what questions did you have? If you have questions for the instructor,
email him directly, in addition to putting these questions in the study log.
Study logs are due each Tuesday, starting on April 9, for the preceding week. They are subject to late penalties. Study logs should be about one third to one half of a page in length. - Apr 1g. The official late penalty is 10% per day that a project is late. Projects will have a three day grade period before they are counted late. If you have extenuating circumstances, late penalties may be reduced if you talk to the professor, either by phone or via Zoom. Although it is possible for the late penalties to be reduced, they cannot be totally eliminated.
- Apr 1h. The last day to drop this class with full tuition refund is Sunday, April 14.
