% Produces four QQ plots for human eye saccade data. Each plot % shows a different transformation, showing that some % transformations get the data closer to a normal distribution. % % Figure caption: Q-Q plots. % % Upper Left: QQ plot for the data from a particular patient, % shown in Chapter 1, from the study by Behrmann et al. (2002) % % Upper Right: QQ plot of the same data following a log % transformation % % Lower Left: QQ plot following a reciprocal transformation. The % plot for the log transformed data is straghter than that for the % raw data; the plot for the reciprocal-transformed data is % straighter still. % % Lower Right: QQ plot % of data from a different patient, which % exhibits an S shape. patient1 = csvread('../data/p3359b.csv', 0, 0); logReactionTimes = log10(patient1); reciprocalReactionTimes = 1 ./ patient1; patient2 = csvread('../data/p3437b.csv', 0, 0); pd = ProbDistUnivParam('normal', [0, 1]); behrmanFig = figure set(gcf, 'Position', [200, 100, 1100, 900]) %% QQ for original data. subplot(2, 2, 1) qq1 = qqplot(patient1, pd); set(qq1, 'Color', 'w', 'MarkerSize', 5, 'MarkerEdgeColor', 'k') set(gca, 'xlim', [-3, 3], 'ylim', [0, 1], ... 'XTick', -3:1:3, 'YTick', 0:0.2:1, ... 'FontSize', 18, 'TickDir', 'out') xlabel('Theoretical Quantiles', 'FontSize', 18) ylabel('') title('') %% QQ for log data. subplot(2, 2, 2) qq2 = qqplot(logReactionTimes, pd); set(qq2, 'Color', 'w', 'MarkerSize', 5, 'MarkerEdgeColor', 'k') set(gca, 'xlim', [-3, 3], 'ylim', [-1.5, 0], ... 'XTick', -3:1:3, 'YTick', -1.5:0.5:0, ... 'FontSize', 18, 'TickDir', 'out') xlabel('Theoretical Quantiles', 'FontSize', 18) ylabel('') title('') %% QQ for reciprocal data. subplot(2, 2, 3) qq3 = qqplot(reciprocalReactionTimes, pd); set(qq3, 'Color', 'w', 'MarkerSize', 5, 'MarkerEdgeColor', 'k') set(gca, 'xlim', [-3, 3], 'ylim', [0, 15], ... 'XTick', -3:1:3, 'YTick', 0:5:15, ... 'FontSize', 18, 'TickDir', 'out') xlabel('Theoretical Quantiles', 'FontSize', 18) ylabel('') title('') %% QQ for another patient's data. subplot(2, 2, 4) qq4 = qqplot(patient2, pd); set(qq4, 'Color', 'w', 'MarkerSize', 5, 'MarkerEdgeColor', 'k') set(gca, 'xlim', [-3, 3], 'ylim', [0, 1.2], ... 'XTick', -3:1:3, 'YTick', 0:0.2:1.2, ... 'FontSize', 18, 'TickDir', 'out') xlabel('Theoretical Quantiles', 'FontSize', 18) ylabel('') title('') % Close device. saveas(behrmanFig, '../figures/behrmanQQ.png', 'png')