<html>
<head>
<title>Simple Linear Regression</title>
</head>
<body bgcolor="white">
<center>
<?php
include "navbar.php";
if (!empty($x_values)) {
$X = explode(",", $x_values);
$numX = count($X);
}
if (!empty($y_values)) {
$Y = explode(",", $y_values);
$numY = count($Y);
}
// redisplay entry form if data not entered correctly
if ( (empty($title)) OR (empty($x_name)) OR (empty($x_values)) OR (empty($y_name)) OR (empty($conf_int)) OR (empty($y_values)) OR ($numX != $numY) ) {
?>
<h2>Simple Linear Regression</h2>
<table border='0' cellspacing='5' cellpadding='0'>
<form method='post' action='<?php echo $PHP_SELF ?>'>
<tr>
<td>
1. Title of Study
</td>
</tr>
<tr>
<td>
<input type='text' name='title' size='30' value='<?php echo $title ?>'>
</td>
</tr>
<tr>
<td>
2. Enter X name
</td>
</tr>
<tr>
<td>
<input type='text' name='x_name' size='30' value='<?php echo $x_name ?>'>
</td>
</tr>
<tr>
<td>
3. Enter comma separated X values
</td>
</tr>
<tr>
<td>
<textarea name='x_values' rows='3' cols='50'><?php echo $x_values ?></textarea>
</td>
</tr>
<tr>
<td>
4. Enter Y name
</td>
</tr>
<tr>
<td>
<input type='text' name='y_name' size='30' value='<?php echo $y_name ?>'>
</td>
</tr>
<tr>
<td>
5. Enter comma separated Y values
</td>
</tr>
<tr>
<td>
<textarea name='y_values' rows='3' cols='50'><?php echo $y_values ?></textarea>
</td>
</tr>
<tr>
<td>
6. Confidence Interval
</td>
</tr>
<tr>
<td>
<input type='text' name='conf_int' size='3' value='<?php echo $conf_int ?>'>%
</td>
</tr>
<tr>
<td align='center'>
<input type='submit' value='Analyse Data'>
</td>
</tr>
</form>
</table>
<?php
} else {
include_once "slr/SimpleLinearRegressionHTML.php";
$slr = new SimpleLinearRegressionHTML($X, $Y, $conf_int);
echo "<h2>$title</h2>";
$slr->showTableSummary($x_name, $y_name);
echo "<br><br>";
$slr->showAnalysisOfVariance();
echo "<br><br>";
$slr->showParameterEstimates($x_name, $y_name);
echo "<br>";
$slr->showFormula($x_name, $y_name);
echo "<br><br>";
$slr->showRValues($x_name, $y_name);
echo "<br>";
include ("jpgraph/jpgraph.php");
include ("jpgraph/jpgraph_scatter.php");
include ("jpgraph/jpgraph_line.php");
// The first graph to display is a scatter plus line plot
$graph = new Graph(300,200,'auto');
$graph->SetScale("linlin");
// Setup title
$graph->title->Set("$title");
$graph->img->SetMargin(50,20,20,40);
$graph->xaxis->SetTitle("$x_name","center");
$graph->yaxis->SetTitleMargin(30);
$graph->yaxis->title->Set("$y_name");
$graph->title->SetFont(FF_FONT1,FS_BOLD);
// make sure that the X-axis is always at the
// bottom at the plot and not just at Y=0 which is
// the default position
$graph->xaxis->SetPos('min');
// Create the scatter plot with some nice colors
$sp1 = new ScatterPlot($slr->Y, $slr->X);
$sp1->mark->SetType(MARK_FILLEDCIRCLE);
$sp1->mark->SetFillColor("red");
$sp1->SetColor("blue");
$sp1->SetWeight(3);
$sp1->mark->SetWidth(4);
// Create the regression line
$lplot = new LinePlot($slr->PredictedY, $slr->X);
$lplot->SetWeight(2);
$lplot->SetColor('navy');
// Add the pltos to the line
$graph->Add($sp1);
$graph->Add($lplot);
// ... and stroke
$graph_name = "temp/test.png";
$graph->Stroke($graph_name);
?>
<img src='<?php echo $graph_name ?>' vspace='15'>
<br><br>
<?php
// Second graph displays residuals as function of predicted Y values
$graph2 = new Graph(300,200,'auto');
$graph2->SetScale("linlin");
// Setup title
$graph2->title->Set("$title");
$graph2->img->SetMargin(60,20,20,40);
$graph2->xaxis->SetTitle("Predicted Y","center");
$graph2->yaxis->SetTitleMargin(40);
$graph2->yaxis->title->Set("Residual");
$graph2->title->SetFont(FF_FONT1,FS_BOLD);
$graph2->xaxis->SetPos('min');
$sp2 = new ScatterPlot($slr->Error, $slr->PredictedY);
$sp2->mark->SetType(MARK_FILLEDCIRCLE);
$sp2->mark->SetFillColor("red");
$sp2->SetColor("blue");
$sp2->SetWeight(3);
$sp2->mark->SetWidth(4);
$graph2->Add($sp2);
$graph_name = "temp/test2.png";
$graph2->Stroke($graph_name);
?>
<img src='<?php echo $graph_name ?>' vspace='15'>
<form>
<input type='Button' value='Back' onClick='history.go(-1)'>
</form>
<?php
}
?>
</center>
</body>
</html>
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