Correlation Coefficients

The correlation coefficient (commonly noted by the Greek letter rho, ρ) measures the degree to which two sets of numbers are related. The correlation coefficient can range from -1.000 to +1.000 with a 0 indicating that there is no relation between the two sets.

In this application, you may relate two or three sets of numbers and the correlations between the sets are shown as ρ(AB), ρ(AC), and ρ(BC), where the letters A, B, and C represent the columns.

There must be at least 3 pairs of numbers in any 2 rows for the correlation coefficient to be computed. Zero is a number but 'n/a' is not. If, for example, Column A has 5 rows of numbers and the 6th row is 'n/a' and Column B has 4 rows of numbers and the 5th row is 'n/a', the correlation coefficient, ρ(AB), will be computed for the first 4 pairs of numbers.

There are two methods of data entry: slider or keypad. Each has different features and benefits.

changes in version 4.0

• Changes necessitated by iOS 13 & 14
• Removed links to Facebook and Twitter
• Various GUI changes and enhancements
• Some code simplification

changes in version 3.0

• Redesigned and rewritten for iOS 7
• Minor bug fixes

changes in version 2.3

• To simplify moving between the two methods of data entry, we have added buttons for "Keypad" and "Slider" in the lower right-hand corner of the data entry views
• On the 'Extended Correlation' view, we added a reminder that a data entry of zero is a number, but a blank data entry is an 'n/a' that removes the entry from the regression computation

changes in version 2.2

• Never mind. Removed upside-down portrait mofe that caused display issues when editing
• Modified syntax of iTunes App Store link

changes in version 2.1

• Added ability to create values with zero to three decimal place precision in the 'Keypad Input' screen and changed the way that numbers are assigned plus or minus signs
• Extended the number of data entries per column from 10 to 12 in the 'Keypad Input' screen
• In 'Keypad Input', removing a data entry with the 'n/a' description is accomplished by making the entry blank
• Improved floating point precision of all calculations from single to double
• Minor GUI changes