Free Software to do Statistical Analysis

Recently I was working on a project which requires analysis of thousands of traffic data. Unfortunately, I have to use Excel since I don't have access to software like SPSS or SAP. Excel gave me a headache because it runs slowly and you cannot easily generate some special graphs and change the settings.
A friend recommended R -a language and environment for statistical computing and graphics developed at Bell Laboratories.
R provides a wide variety of statistical (linear and nonlinear modelling, classical statistical tests, time-series analysis, classification, clustering, ...) and can produce well-designed plots. Users have full control (I like it!).
Most of all, it is Free Software :)

Nice tool to manage group money: Scred

A few weeks ago I had a wonderful vacation with a group of friends. We shared expenses during the trip. And as you can imagine, dealing with the receipts and costs afterwards was a headache.
Fortunately, one friend introduced Scred , which is a web tool for recording shared expenses and debts, tracking transactions, and providing pay back suggestions. We saved a lot of time and efforts by using this tool to get the pay back amounts. Then we sent payments via Amazon Payment or bank transfer.
Nice tool really worth to recommend!

A free tool to split audio file

I needed to divide a 2-hour .WAV file into smaller files. It didn't take me very long to find this free software online: Audacity.
Step 1: File-Open-Select the WAX file
Step 2: Place labels where I want to split the file
Place the cursor, press Ctrl+b, optionally type a name for the label
Step 3: File-Export multiple
In the dialog, set
Split files based on: "labels", check "Include audio before first label"
Name files: Numbering consecutively
Step 4: Press Export.

Thank vanadium for recommending this tool. (http://ubuntuforums.org/showthread.php?t=421265)

Using Online Poll to Schedule Events

Here is the website where I create an online poll to schedule events:

https://www.doodle.com/

Tips:

1. The available time of the first person to participate in the poll is quite important because the others would just narrow down the time windows.
2. Set up narrow time slots if possible.

How to make animated gifs?

I just learned an easy way to create animated gif pictures:
Tool: GIMP ( GNU Image Manipulation Program)
Step1:
Prepare several pictures as the frames, e.g. p1.png, p2,png.
Step 2:
File->Open->"p1.png"
Step 3:
File->Open as Layers->"p2.png"
Step 4:
Image->Mode->Indexed
Step 5:
Save as->"test.gif"->Save as Animation->Export->
Adjust the parameters, for example
"loop forever"
"Frame disposal where unspecifed: One frame per layer (replace)"

Google Earth Tools

Google Earth is a useful and powerful tool. Recently I am working on Google Earth Pro. Here are their additional functions compared to the free version:
(1) Measure polygons and circles;
(2) Print high-resolution image;
(3) Import spreadsheet files and GIS shape files;
Does this Pro license really deserve 400$/year? Well, it does save a lot work load. But those functions can also be done by using some online tools or coding kml/kmz files.
I am not familiar with Google Earth API and those coding stuff. But here are some useful tools I found from ...Google....
(1) KML Circle Generator
It'll generate a LineString path for you that looks just like a circle.
(2) Earth Point Tools: Calculate Polygon Area
Calculate the area of a Google Earth polygon, its perimeter, centroid, and bounding box.
Calculate the length of a path, its mid-point, and bounding box.
You can measure multiple polygons in one folder at one time, and export the results in excel files. Amazing!
(3)Earth Point Tools: Create Directional Arrow
Export a spreadsheet of lat/long coordinates to Google Earth. Pop-up balloons, icons, paths, and directional arrows are easily created from the spreadsheet data.
(A lot of other small but powerful tools can be found in this website. )