iPhone / iPad Scientific Calculator for Error / Uncertainty Propagation and Analysis



ErrorCalc is a scientific calculator app for iPhone, iPad, iPod touch that is designed for error/uncertainty propagation and analysis of experimental data sets.  All values entered into the calculator can include error/uncertainty, which will be propagated during successive calculations. In addition to 
https://itunes.apple.com/us/app/errorcalc-scientific-calculator/id597254824?ls=1&mt=8
ba sic arithmetic functions, trigonometric and exponential/logarithmic functions can be calculated. The app can also calculate both weighted and unweighted means/standard deviations for experimental data sets.

In addition to standard algebraic entry mode (ALG), will allow Reverse Polish Notation (RPN) entry mode (which is common on HP Calculators).  

There is also a Free version of ErrorCalc that allows uncertainties in Multiplication, Division, Addition and Subtraction of numbers.  Numbers can be written in scientific notation.  




                                                                                             
Entering Values
  • Top line of screen (yellow background) shows status.
  • Lower pair of lines (white and gray) are for values (upper line) and for error (lower line)
  • The active entry line has white background

To enter the value 9.8 with an uncertainty of 0.1

  • Touch upper display line (its background will be white)
  • Then type 9.8
  • Touch lower display line for errors (which will then change to white leaving the upper line gray)  
  • Then type 0.1

Alternately, press the ± label to toggle between value and error lines

Touch ALG to toggle between ALGebraic and RPN modes

-------- ALGebraic Mode Calculations ---------

Example: To calculate  4±0.1 - 2±0.1
  • Enter the value 4 (in the upper of the pair of lines)
  • Then touch the lower line and type in 0.1 for the error.  
  • Next press the plus key
  • Finally, type 2 in the upper line for the value
  • Enter 0.1 in the lower line
  • Pressing = gives a result of 2.0 ± 0.1414

  • ErrorCalc does not allow mixed mode operations such as multiplication followed by addition without equal sign

  • Equations with several sequential Multiply/Divide or Add/Subtract are allowed without intermediate equal signs.     
    • For Example:   

        3 / 4 * 2 / 5 = Gives 0.3

        3 - 4 + 2 - 5 = Gives -4

        3 / 4 * 2 + 5 Gives Error (since it is mixed mode once the + sign is pressed)

  • Sample Mixed Mode Calculation: To calculate the value of sin(30±2 - 20±1) / (4.0±0.1 - 2.0±0.1)
    • First calculate:  4±0.1 - 2±0.1  =   which gives 2.0 ± 0.1414
    • Store in memory using  Mem followed by MCl (if needed) and M+ to add to memory
    • Next calculate 30±2 - 20±1 = which gives 10.0 ± 2.236
    • To take the sine, Set D/R rocker to D (Degrees)
    • Press Func then Sin  which gives 0.17365 ± 0.03843
    • Finally press divide button and Mem MRcl to recall giving a final result of 0.0868 ± 0.0202


  • To Scroll Through Previous Values and Results
    • Touch finger and drag up or down in the region of the screen near value and error displays.
-------- RPN Mode Calculations ---------

Example: To calculate  4±0.1 - 2±0.1
  • Enter the value 4 (in the upper of the pair of lines)
  • Then touch the lower line and type in 0.1 for the error.  
  • Next press the Enter key to push the value onto the stack
  • Finally, type 2 in the upper line for the value
  • Enter 0.1 in the lower line
  • Pressing - subtracts gives a result of 2.0 ± 0.1414
  • Sample Mixed Mode Calculation: To calculate the value of sin(30±2 - 20±1) / (4.0±0.1 - 2.0±0.1)
    • First calculate:  30±2 ENTER 20±1 - (Minus sign) which gives 10.0 ± 2.236
    • To take the sine, Set D/R rocker to D (Degrees)
    • Press Func then Sin  which gives 0.17365 ± 0.03843
    • Press Enter to push this value to the stack
    • Next calculate 4.0±0.1 Enter 2.0±0.1 - (Minus sign) which gives 2.0 ± 0.1414
    • Finally press divide button giving a final result of 0.0868 ± 0.0202

-------- Other Features ---------
The Func button enables keys to allow calculation (with uncertainty) of trigonometric and exponential functions.
  • The D/R toggle switches between Degrees and Radians for trig functions
  • Ln calculates Natural Log
  • Log calculates Common (base 10) Log"
The Mem button allows values to be stored to memory, recalled and cleared.  
  • (The Mem button will be bright red when a value is stored and dim red if memory is clear)
  • M+ : Adds value (and error) to memory
  • M- : Subtracts value from memory
  • MClr : Clears Memory
  • MRCl : Recalls Memory Value
  • Prev and Next : Cycles through previous results
  • Click : Turns Clicks on/off\
  • Ave : Enters the Average Mode (see below for details)
  • Reset : Resets Calculator to its initial state
  • Help : Enters Help Screen (can also use the "i" button)

Statistics (Weighted and Unweighted)  
  • On iPhone: To get to Average mode, Press Mem,  then Ave
  • Enter Each Value then Press Data+ (to delete a point on iPad, use Data -)
  • SCalc to Calculate statistics
  • Press StatCl to Clear Statistics
  • On iPhone, Press Exit to leave the statistics mode.

  • For Unweighted Statistics, Do Not Include Errors
  • The resulting calculation is the unweighted mean, and the Sample Standard Deviation
  • Sample Data Set: 1, 2, 3  Gives the Result: Ave=2, StdDev=1

  • For Weighted Statistics, Include Error for Each Value
  • Sample Data Set: 1±0.1, 2±0.2, 3±0.3 Gives the Result: Ave=1.3469, StdDev=0.0857

Contact Information:  Error.Calculator@gmail.com           © Thomas Huber, 2013


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Since January 2013