# Chi-Square Goodness-of-Fit Test Using TI-84+

There was some recent confusion about a problem in MyMathLab.

# Golden Ratio Calculations using TI-34Multiview

Even with a nice calculator like the TI-34Multiview, some expressions can still be tricky to enter into the calculator.

# Regression on the Calculator

Here are a few notes on regression and other stuff I’ve noticed over the past week:

1.  Remember my calculator post from last week?  Well, some of my Finite Math students were still having a little bit of trouble using the calculator to do Regression on the calculator.  This website on Cubic Regression seems to have done the trick for my students, and I don’t seem to be getting nearly as many questions about how to do regression on the calculator now have I have started to circulate this link around.  So, I figured I would throw it out there as a resource for everyone else!

2.   If you have a student who needs extra help and you aren’t fortunate enough to be teaching from a Pearson book that uses MyMathLab, you can always send your students over to InteractMath.  The student just needs to choose a book with similar topics to that of which you are studying, and exercises will be generated from there.  Actually, I’m using it in the on-line class I’m designing this semester because part of the challenge of creating this class is that we are supposed to use strictly free, on-line resources.  And this definitely qualifies!

3.  Eh, if you’re reading this, check out this great Math Magic Trick and list of Five Things to Do with Your Old Laptop.  I know, both are very random links, so I’ll tag them as #miscellaneous, how about that?

# Graphing Calculator Issues

In my Finite Math class I have been heavily stressing the use of the graphing calculator, especially since the college requires the calculator for the course.  I would definitely show the students how to use the graphing calculator anyway, it’s just that since it’s required, I feel as if I have an extra obligation to make sure that the students are using the calculator that they spent their big bucks on.  Anyway, here are a few issues that I have run into so far this semester (and unfortunately, I ran into all of the issues on the same night so it totally looked like I didn’t know what I was doing):

Issue #1:  When using ‘Math Print’, the Radical Sign has a limit.

My calculator is the TI-84+, which has the operating system upgrade.  Of course my calculator was in the new ‘Math Print’ mode since that is the default.  If you know anything about this mode, you will know that the square root symbol shows up on the screen, instead of having to put parentheses around the radicand.  Well, guess what?  There’s a limit to how many characters can go under the radicand.  And the calculator doesn’t really indicate this until you’ve typed in all of the characters and then realize that the radical symbol isn’t covering the entire radicand.
I tried to calculate the radical anyway, despite realizing that the radical symbol wasn’t covering the entire radical.  And my answer was wrong, and I looked somewhat like a fool for giving an answer that was clearly incorrect.  So, please be wary of the lure of the new ‘Math Print’ mode.

Issue #2:  When graphing piecewise functions, compound inequalities can be tricky.

When I first got my textbook for this semester, I was quite excited because the book came with many resources, including a graphing calculator guide.  I printed the guide out immediately, and figured that I could refer to it as needed throughout the semester in case I forgot one of the commands.  I also figured that the guide would provide some tips and tricks to using the graphing calculator specifically for the textbook that I might not know about.  One of these things is graphing piecewise functions, as I have never done this in the calculator before this semester.
Before class, I thought I was prepared.  I practiced entering piecewise functions and I reviewed my guide.  However, once in class, I totally froze up when entering piecewise functions.  So, I referred to my guide, and the one thing I needed it for, it didn’t cover – entering the pesky compound inequalities.  I knew I had done it before and that there was something I just wasn’t remembering.  Well, good thing for me one of my students figured it out in a rare ‘aha’ moment.  Really, I don’t get those too much in my classes.  But this student is a really great student, so I gave her big props for figuring the fix out before I did.
Anyway, you may want to review this document if you ever intend on doing a live demo of piecewise functions in the classroom:  http://www.tc3.edu/instruct/sbrown/ti83/funcpc.htm.

Issue #3:  Some graphing calculators display asymptotes (by default) and some don’t.

It dawned on me on the spot, right then and there, that the TI-83 calculators display the asymptotes by default.  Of course!  That’s why the graphs look different.  Although, if I would have known how to at the time, I would have probably told the students with the TI-84 calculators to turn the asymptotes on so that everyone could see the same graph.  And here’s a post from the TI people on how to do that:  http://bit.ly/hls6ui.

# Mid-Week Ideas, Anyone?

A couple of things I came across this week.  Of course, there were more, but here are the highlights:

1.  TI-Nspire Videos over at Atomic Learning – These are wonderful walk-through videos which cover the basics, graphs and geometry, lists and spreadsheets, data and statistics, calculator and data collection.

2.  TopicMarks – I heard about this wonderful tool this week in my Twitter feed that summarizes text documents for you.  This has wide implications, such as allowing more free time to read other materials, or to just simply give an abstract for one of your own works.

3.  Inequality Match Game – I actually found the direct link for this game from the North Carolina Public Schools first, and then hunted down the original source once I realized that the wonderful state of North Carolina has come up with what seems to be hundreds of activities for teaching math.

After a recent afternoon meeting about statistics, I needed to find a few old links that I had buried away.  Well, here are a few odds and ends I found while looking:

1.  Virtual Math Lab at Texas A&M – This is a very good resource for College Algebra, Intermediate Algebra, and Beginning Algebra.  When I opened my link, it actually opened on ‘Absolute Value Equations’, which means that’s probably what my students were struggling with when I initially discovered this website back in 2009.

2.  Quick-and-Dirty Guide to the TI-83, TI-83+, TI-84, and TI-84+ – Although it seems like it would be most useful for the beginning calculator student, I have to say that the time I used this website the most was when I taught Calculus, and I couldn’t remember many of the calculus-related functions.

3.  Pete Falzone’s On-line Office – I have been borrowing handouts from this guy for the longest time. The pre-algebra resources are especially good for developmental math classes.  And I have found a lot of other great worksheets for other courses for when I have been called to substitute at the last minute and needed an ‘in a pinch’ lesson outline.

4.  Project-Based Learning – I am obviously all for project-based learning.  But if you need a little more background information, along with some additional examples and ideas for your mathematics classroom, feel free to visit this website.  There is a good description of project-based learning, along with some wonderful links to helpful websites.

5.  Classroom Assessment Techniques – This is definitely worth checking out, as I know that I got at least a couple of ideas from this website for the times when I knew that I had to do an in-class assessment, but needed something that was quick to set-up (I usually realize things 1/2 way into class for some reason).

6. Quiz Star and Easy Test Maker – Two quick links to create on-line and off-line quizzes and tests.  Both are free.  I know, I know, you probably don’t need another free product to do this, as you already have your own Course Management System, or you have your own system for creating tests.  That’s fine, but these may be useful if you’re looking to do something different.