Texas Instruments TINSPIRECX manual Charts with Two Variables, Fitting a Line by Hand and Eye

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Charts with Two Variables

Create a new Data & Statistics page.

Notice both axes are marked Click to add variable.

As before select mshoe for the horizontal axis.

Move the cursor to the left edge of the screen, click x and select the variable mhand for the vertical axis.

This displays the scatterplot.

First Steps with TI-Nspire™

Tutorial 7: One- and two-variable statistics

Ready to add a 2nd variable

It may be that there is a positive correlation and a relationship between hand span and shoe size, so it may be appropriate to model this relationship with a linear function. The Analyze menu provides a range of tools to use.

Fitting a Line by Hand and Eye

First try adding a line of best fit by eye, using option

2:Add Movable Line. This displays a straight line together with a functional relationship between mshoe and mhand. The line can be dragged into a best-fit position using the two cursors for rotate and translate, in exactly the same way as a straight line can be moved manually in the Graphs and Geometry applications.

Translating the line

Powerful options in the Analyse menu

Rotating the line

Move to the middle of the line to get the translate cursor. Click and hold x to grab it. Now move the line into position. Click again x to release the cursor.

Move towards one end of the line to show the rotate cursor. Click and hold x to grab it. Use the Touchpad to rotate the line.

Click again x to release the cursor.

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© 2012 Texas Instruments Education Technology

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Contents First Steps About this document Contents Appendix TI-Nspire CX Keypad Layout TI-Nspire Documents Nothing on the screen?Memory Battery Life Charging the handheldHome Screen First Steps with TI-Nspire Tutorial 1 TI-Nspire documents Documents, Problems and Pages ScratchpadNavigating Documents First Steps with TI-Nspire Tutorial 1 TI-Nspire documents Contextual Menus Check list of some key points in Tutorial Calculator Application Basic operationsHistory Lesson Approximate CalculationsTemplates Menu of maths templatesDocument settings dialog box Effect of changed settingsGetting Set Some Algebra Ways to define variablesUse of function notation Calculator Menu Statistical Distribution TablesLists of random integers Variables Linked to Documents List of defined variablesWhy use Notes? Making NotesVarious text formatting Instructions Recording results Splitting the Screen Format sub-menuWays to split the screen You must press /e and then b An inserted comment Use of proof template and symbols More Options from the Notes MenuInteractive Notes Use of Q+A templateAsking Questions Check list of some key points in Tutorial Graphing Graphs & Geometry Two ViewsGraphing Functions Graphing ViewGrab and Drag Practice Changing the AxesOpen-hand cursor Grabbed tick mark on the axesZoom settings Grabbed-sheet icon Editing, Deleting or Hiding a FunctionChanging f2 in the function history Tracing Graphs Points and coordinatesTrace picks out significant points Points of intersectionAnalyse Graph Menu Coordinates and labelled pointsUsing Sliders Manually Moving GraphsAlternative icons Transformed graph and equation Sequence Plotting Check list of some key points in Tutorial Geometry View for Plane GeometryTwo Parallel Lines Drawing the base of the triangleWhat’s grabbable? Construct the TriangleMany options in the Construction menu Making Measurements Variables and TextMeasurement menu Storing the measurement as a variableTidying Up and Using Attributes Dynamic ChangesReady to grab a and slide it Changing the attributes of the triangleArea is now locked Unlocked/Unpinned Points B and C. Try Moving point BCheck list of some key points in Tutorial Lists & Spreadsheet Entering Data as ListsUsing Formulae Conflict resolutionOne way to enter a formula Typical Spreadsheet Actions Capturing Data Function TablesHand-made function table Simple function table Options for function tables Graph and table side by sideFrequency Charts Charts with One Variable One and Two Variable StatisticsShoe Sizes and Hand Spans Charts for Categorical Data Pie Chart displaying categorical dataComparing Boxplots Upper quartile displayedCharts with Two Variables Fitting a Line by Hand and EyeReady to add a 2nd variable Drawing the Regression Line Getting the StatsCalculated regression line Statistics Calculations menu Dragging on the Charts Working with Frequency DataSets of statistics Effect of moving a point from here … … to hereTexas Instruments Education Technology Check list of some key points in Tutorial Multiple Representations Draw and Measure a CircleMeasured circle Setting up a scatter plot Data capture is under way Spreadsheet for Data CaptureTwo Scatterplots Collecting Just a Little DataGo to Town with Data Collection Fit a Straight LineLinear relationship Moving a straight line by hand Not a linear relationshipDifferent Approach to Scatterplots RegressionBasic quadratic ready for fitting… … and dragged into place