How to Easily Find Averages on your Graphing Calculator.

If you work with large sets of numbers, then you will probably have to find averages, arithmetic means, and other measures of central tendancy. Unfortunately, this is often a tedious task, and can be quite a pain. With the development of new calculators, however, there are now operations that will simply do it for you at the click of a button.

First, what you will want to do is enter all of your data. On new calculators such as the nSpire series, you can simply load a spread sheet onto the calculator. For older models you will have to manually enter them into your "L1," or list one. Make sure to enter all of you data accurately.

Next, you will want to find the "One-Variable Statistics" command. On the nSpire series, this is under menu -> Stat Calculations. It's the very first option. When you are under the command, you will be able to select what list you want to use, or on newer models with the spreadsheet app, it will allow you to select how many lists there are, and what lists you want. Then hit enter.

This command will allow you to see all the stats you would need for your data including arithmetic mean (x bar), median, standard deviation, and other less common stats. Enjoy!

TI nSpire CX Review

The TI nSpire series calculators are by far some of the best out on the market right now. With a sleek design, and a beautiful color display, the difference between them and the competition is very apparent. Also, with a new design comes a great new feature; a rechargable battery.

The screen is 320x240 pixels, and displays in 125dpi; 16 bit color. Not bad at all considering the screen is sitting in a calculator. As for the battery, its a very long life unit produced by TI. The CPU in the device runs at an impressive 150MHz ARM processor, and for system memory you get 64MB of ram, and an additional 100MB for storage.  On the top side of the device is a mini USB port to connect to the charger or a pc, and another port for attachments to the calculator. The device also comes with emulator software for a pc that allows you to better manage files, as well as load games, other applications and software onto your device.

In my time with the CX, it's been an overall great experience. Out of the box you will need to do some setting up such as setting the mode to degree instead of radians, and other very simple things. After you are done configuring the calculator to your liking, you will have a fully functioning device.

The operating system on the device is very simple to learn and use, but it will take some getting used to. Instead of hardware buttons for most functions, you instead get a menu button and expanding menus. Functions such as nCr has instead been moved under a 'probability' menu. It's easy to use, but you'll find yourself looking for buttons that aren't really there.

As for external build quality, it's pretty hard to beat Texas Instruments. The device feels solid, and has some weight to it. The buttons don't give a very satisfying click with good feedback unfortunately, but this is due to the new slim design. Most users would prefer a sleek device with mediocre buttons over a chunky device with great buttons anyways. The directional d-pad is located in a great area, and it's touch sensitivity is a great feature that allows navigating and editing long equations or browsing menus a breeze. The plastic of the touch pad is slick and doesn't attract finger prints at all, but I would have preferred a less sensitive setting, or to be abel to adjust the sensitivity of the cursor. The plastic protecting the screen isn't the best, and is my only real nag about the device. On the second day with the CX I managed to scratch the screen by accidental putting the plastic cover on the wrong way. I was surprised that the soft plastic case could cause such a big scratch going from the top of the device to the middle of the screen. Oh well, accidents happen, but I would recommend buying a screen cover for your calculator as soon as you get it.

Overall, I found the TI nSpire CX to be a great calculator for it's price, and to be a surprisingly capable device.

To CAS, or not to CAS? That is the question.

When you buy a modern calculator, one of the first things you'll have to consider is whether to go with a slightly more expensive CAS model, or stick with the base model. Well, to make this decision, you will need to take a few things into consideration.

First, what is CAS? Well, this acronym stands for Computer Algebra System. In a very basic sense, this system allows the calculator to recognize non-numerical symbols, and solve algebra for you. Pretty sweet, huh?

So, as a student, this feature might be of great benefit to you. Let's say you're a student and you are given a formula and a problem. With a CAS calculator, you can type the formula directly into the calculator, specify the variable(s), and it will solve it for you. The system can pretty much tackle anything you will encounter as a student including polynomials in multiple variables; standard functions of expressions (sine, exponential, etc.); various special functions (Γ, ζ, erf, Bessel functions, etc.); arbitrary functions of expressions; optimization; derivatives, integrals, simplifications, sums, and products of expressions; truncated series with expressions as coefficients, matrices of expressions, and Numeric domains supported typically include real, complex, interval, rational, and algebraic.

So how does this magical feature work? Here are a few simple steps to get you going. Keep in mind I'm on a Texas Instruments Nspire CX CAS.

Lets say this is your problem:
Side A of a triangle is 7 feet, and the hypotenuse is 15 feet. What is side B?

First, you're going to open up the calculator program, and hit the 'menu' button. Then select "Algebra."

Next, select the sixth option called "Numerical Solve."

In the parenthesis, start to enter your equation. In this case it would look like this: nSolve(7² +b² =15²)

Now define the variable. Add a comma, and then the variable you used. nSolve(7² +b² =15²,b)

Hit enter, and if you did everything right, it will spit out the length of side B; 13.27 feet.

As you can see, I simply used the letter keys to enter the variable 'b,' and for the equals sign, I used the equals symbol button at the top left of the keypad, NOT the enter button. Remember to keep the entire equation inside the parenthesis, and to define your variables with a comma, then the variable you used.

So, if it were my choice, I would say go with a CAS calculator. As a student it simplifies my work, and saves me a lot of written work that you would have to do with a more basic calculator. CAS enabled devices usually cost a bit more than their counterpart as well. The choice is yours!