- java.lang.Object
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- java.awt.Component
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- java.awt.Container
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- java.awt.Window
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- java.awt.Frame
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- javax.swing.JFrame
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- FriedmanGUI
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- All Implemented Interfaces:
- java.awt.event.ActionListener, java.awt.event.FocusListener, java.awt.event.ItemListener, java.awt.image.ImageObserver, java.awt.MenuContainer, java.io.Serializable, java.util.EventListener, javax.accessibility.Accessible, javax.swing.RootPaneContainer, javax.swing.WindowConstants
public class FriedmanGUI extends javax.swing.JFrame implements java.awt.event.ActionListener, java.awt.event.FocusListener, java.awt.event.ItemListener
Friedman - GUI Version
Summary
- A utility to perform a Friedman test on a table of data
Background
The Friedman test is a non-parametric statistical procedure to assess the difference between three or more correlated samples, which is to say, between three or more conditions assigned within-subjects. The relationship with other non-parametric tests is illustrated below:Design Conditions (samples) 2 3 or more Between-subjects
(independent samples)Mann-Whitney U Kruskal Wallis Within-subjects
(correlated samples)Wilcoxon
Signed-RankFriedman The procedure involves converting the raw data to ranks. The conversion is done row by row, which is to say, participant by participant. The ranks are then compared by columns to determine if there is a significant difference between conditions.
The test is intended for ordinal data, such as rankings, assessments, or questionnaire responses (where the responses are non-linear). Using the Friedman test (or other non-parametric tests) for interval or ratio data over a parametric ANOVA is an option if there is a concern over the underlying assumptions in the distribution of the data. The researcher must bear in mind, however, that the data transformation bears a cost: Information is sacrificed. For example, interval or ratio scores of 80, 79, and 49 are converted to ranks 1, 2, and 3. Yes, information is sacrificed.
Launch FriedmanGUI from GoStats as follows:
Example 1
Consider an experiment where four new search engines were compared for "quality of results". Quality of results was assessed on a scale from 0 to 100 (higher scores preferred). For the assessment, eight participants were recruited and then trained and tested on each search engine. Since the search engine condition was assigned within-subjects, counterbalancing was used (although this is not important here). The assessments are stored in the GoStatsExamples folder in a file named friedman-ex1.txt. The data are organized with one row per participant and one column per condition:66 80 67 73 79 64 61 66 67 58 61 67 71 73 54 75 72 66 59 78 68 67 57 69 71 68 59 64 74 69 69 66The mean scores (not shown) were 71.000, 68.125, 60.875, and 69.750 for search engines #1 (left) through #4 (right). Evidently, search engine #1 did quite well, search engine #3 not so well. But, were the differences in scores statistically significant or were they perhaps just due to chance? This is determined using the Friedman test:
The Friedman test statistic (H) follows the chi-square distribution with k - 1 degrees of freedom (k is the number of columns or conditions). The output also shows the test statistic corrected for ties (H'), with ties computed row by row. There are only two ties (row 3 and row 8), so the correction is minor.
As seen above, the test reveals a significant difference in the quality-of-result assessments between the four search engines (χ2 = 8.692, p < .05, df = 3). A post hoc multiple comparisons test is used to determine which search engine interfaces are significantly different from one another (see below).
Post Hoc Comparisons
A post hoc pairwise comparisons test is added by selecting the output option "Post hoc tests". The tests use Conover's F at α = .05 for a two-tailed test. Here's an example for the above data set:
Pair n:m is a comparison between the search engines in columns n and m. As shown, the comparisons are deemed significant between the search engines in columns 1 and 3 and in columns 3 and 4. The verbose option (see below) provides a rough verification of this, since the mean score in column 3 is the lowest and the mean scores in columns 1 and 4 are the two highest.
StatView provides the following output using the above data set:
- Author:
- Scott MacKenzie, 2012-2023
- See Also:
- Serialized Form
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Field Summary
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Fields inherited from class java.awt.Frame
CROSSHAIR_CURSOR, DEFAULT_CURSOR, E_RESIZE_CURSOR, HAND_CURSOR, ICONIFIED, MAXIMIZED_BOTH, MAXIMIZED_HORIZ, MAXIMIZED_VERT, MOVE_CURSOR, N_RESIZE_CURSOR, NE_RESIZE_CURSOR, NORMAL, NW_RESIZE_CURSOR, S_RESIZE_CURSOR, SE_RESIZE_CURSOR, SW_RESIZE_CURSOR, TEXT_CURSOR, W_RESIZE_CURSOR, WAIT_CURSOR
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Fields inherited from class java.awt.Component
BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method and Description voidactionPerformed(java.awt.event.ActionEvent ae)voidfocusGained(java.awt.event.FocusEvent fe)voidfocusLost(java.awt.event.FocusEvent fe)doublegetCriticalT(int df)Return the critical t statistic, assuming a two-tailed test with α = .05.voiditemStateChanged(java.awt.event.ItemEvent ie)doublemean(double[] n)Calculate the mean of the values in a double array.-
Methods inherited from class javax.swing.JFrame
getAccessibleContext, getContentPane, getDefaultCloseOperation, getGlassPane, getGraphics, getJMenuBar, getLayeredPane, getRootPane, getTransferHandler, isDefaultLookAndFeelDecorated, remove, repaint, setContentPane, setDefaultCloseOperation, setDefaultLookAndFeelDecorated, setGlassPane, setIconImage, setJMenuBar, setLayeredPane, setLayout, setTransferHandler, update
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Methods inherited from class java.awt.Frame
addNotify, getCursorType, getExtendedState, getFrames, getIconImage, getMaximizedBounds, getMenuBar, getState, getTitle, isResizable, isUndecorated, remove, removeNotify, setBackground, setCursor, setExtendedState, setMaximizedBounds, setMenuBar, setOpacity, setResizable, setShape, setState, setTitle, setUndecorated
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Methods inherited from class java.awt.Window
addPropertyChangeListener, addPropertyChangeListener, addWindowFocusListener, addWindowListener, addWindowStateListener, applyResourceBundle, applyResourceBundle, createBufferStrategy, createBufferStrategy, dispose, getBackground, getBufferStrategy, getFocusableWindowState, getFocusCycleRootAncestor, getFocusOwner, getFocusTraversalKeys, getIconImages, getInputContext, getListeners, getLocale, getModalExclusionType, getMostRecentFocusOwner, getOpacity, getOwnedWindows, getOwner, getOwnerlessWindows, getShape, getToolkit, getType, getWarningString, getWindowFocusListeners, getWindowListeners, getWindows, getWindowStateListeners, hide, isActive, isAlwaysOnTop, isAlwaysOnTopSupported, isAutoRequestFocus, isFocusableWindow, isFocusCycleRoot, isFocused, isLocationByPlatform, isOpaque, isShowing, isValidateRoot, pack, paint, postEvent, removeWindowFocusListener, removeWindowListener, removeWindowStateListener, reshape, setAlwaysOnTop, setAutoRequestFocus, setBounds, setBounds, setCursor, setFocusableWindowState, setFocusCycleRoot, setIconImages, setLocation, setLocation, setLocationByPlatform, setLocationRelativeTo, setMinimumSize, setModalExclusionType, setSize, setSize, setType, setVisible, show, toBack, toFront
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Methods inherited from class java.awt.Container
add, add, add, add, add, addContainerListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getAlignmentX, getAlignmentY, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalPolicy, getInsets, getLayout, getMaximumSize, getMinimumSize, getMousePosition, getPreferredSize, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, print, printComponents, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusTraversalKeys, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setFont, transferFocusDownCycle, validate
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Methods inherited from class java.awt.Component
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, disable, dispatchEvent, enable, enable, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocation, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, prepareImage, prepareImage, printAll, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, requestFocus, requestFocusInWindow, resize, resize, revalidate, setComponentOrientation, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeysEnabled, setForeground, setIgnoreRepaint, setLocale, setMaximumSize, setName, setPreferredSize, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle
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Method Detail
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actionPerformed
public void actionPerformed(java.awt.event.ActionEvent ae)
- Specified by:
actionPerformedin interfacejava.awt.event.ActionListener
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focusGained
public void focusGained(java.awt.event.FocusEvent fe)
- Specified by:
focusGainedin interfacejava.awt.event.FocusListener
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focusLost
public void focusLost(java.awt.event.FocusEvent fe)
- Specified by:
focusLostin interfacejava.awt.event.FocusListener
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itemStateChanged
public void itemStateChanged(java.awt.event.ItemEvent ie)
- Specified by:
itemStateChangedin interfacejava.awt.event.ItemListener
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mean
public double mean(double[] n)
Calculate the mean of the values in a double array.- Parameters:
n- a double array- Returns:
- a double equal to the mean of the values in the array.
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getCriticalT
public double getCriticalT(int df)
Return the critical t statistic, assuming a two-tailed test with α = .05.The method uses a lookup table obtained from
http://www.math.unb. ca/~knight/utility/t-table.htm
- Parameters:
df- the degrees of freedom for the t statistic- Returns:
- the t statistic
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