DataAnalysisLite vs Line

DataAnalysisLite is the iPhone version of the DataAnalysis iPad App. DataAnalysisLite is a general purpose App for the plotting and fitting of all types of data that can be formulated as x, y pairs. The program can be used easily by both students and professionals. It is particularly useful for quick analyses of various types of data by curve fitting, value prediction via a standard curve, and analysis of kinetic data including enzyme kinetics. Data can be entered directly via the keyboard or imported from the Mail, or other Apps as a text file (.txt), or a comma separated value file (.csv). Data files in txt, csv and native formats can be directly exported/imported to/from Dropbox and Google Drive. After data entry, the user has the option to average, baseline correct, and/or normalize the data before plotting and fitting. Plotting of the data is as simple as pressing the Plot button. The axes are autoscaled and the graph is immediately ready to add to a document or presentation. The user has a variety of options to customize the graph by altering the axes, axes labels, graph title, and changing the symbols and colors. The data can be fit to a variety of mathematical equations by non-linear regression including simple functions such as linear, 2nd and 3th order polynomials and exponential functions. Data can also be fit to more complex equations for such processes as radioactive decay, enzyme kinetics, as well as 1st and 2nd order chemical reactions. The fit can be overlaid on the data with different line widths, line types, colors and thicknesses. Lowess Regression (LOcal Weighted regrESSion) can also be used to fit data without the need to specify a mathematical function. Not only does Lowess Regression not require a mathematical function, but also does not require parameters (non-parametric). This fitting method is used extensively to fit everything from election polling to astrophysics data, where the data have a large degree of scatter. For many analytical situations, the data fit can be used as a standard curve to determine the value of unknowns. This analytical procedure is completely automated within DataAnalysisLite. The program output, graphics and text, can be copied, emailed, or uploaded to a variety of Apps including Dropbox, Google Drive, Evernote and the Files App in a variety of formats. The graphics in PDF format can be edited with programs like Adobe Illustrator™ and AutoDesk Graphic™ as objects. DataAnalysisLite also supports multitasking and printing of input data as well as all forms of output. An in App HELP system is available that integrates with the DataAnalysisLite User Guide (http://www.scidataanalysis.com/iPhone/user_guide.html).

The Line-Fit app uses linear regression to model the relationship between two variables (x and y) by fitting a linear equation to observed data. One variable is considered to be an explanatory (independent) variable, and the other is considered to be a response (dependent) variable. A linear regression line has an equation of the form Y = a + bX, where X is the explanatory variable and Y is the dependent variable. The slope of the line is b, and the intercept is a (the value of y when x = 0). To measure the association between the two variables the correlation coefficient is used, which is a value between -1 and 1 indicating the strength of the association of the observed data for the two variables. The coefficient of determination, R2, measures how close the data are to the fitted regression line. In general, higher values of R2 indicate a better fit of the model to the given data. R2 is always positive and equal to 1.0 for a perfect fit.