KoalaCalc Classic for Mac

From Macropod Software:

Introducing KoalaCalc Classic, the long-awaited Mac OS 9 port of the free multi-purpose calculator for Mac OS X. In its compacted state, KoalaCalc looks similar to the standard calculator that comes with the Mac OS. However, simply click the 'advanced' button and KoalaCalc comes to life to become one of the most advanced scientific, conversion, statistical and expression calculators available. The list of features includes:

• Numerous mathematical functions including trig and log functions plus 10 individual memory banks
• Conversion to and from dozens of units (inches to millimeters, pounds to kilograms, etc.)
• currency conversions, which can be updated via Internet to current International Monetary Fund exchange rates
• Basic statistical calculations on up to 10 data sets including t-tests and analysis of variance (ANOVA)
• Built-in tape recorder (contents can be saved or printed)
• Voice recognition input (great for people with limited use of their hands)
• Voice feedback (button pressed and/or computed value can be read aloud)
• Built-in expression calculator which supports brackets and the order of operations rules
• Probability calculator computes exact p value based on the F distribution, with or without epsilon correction
• Customizable constants menu
• No 2nd function button - all features have their own button!
• Most buttons include keyboard shortcuts - a real time saver for repetitive calculations
• Help on how to use each button is provided by simply leaving the mouse cursor over a button for a few seconds
• User can set various preferences
• Advanced features can be hidden to reduce the size of the footprint