function ab_test_conversion_rate($test, $alt)
{
$p = (int) ab_tests_total_participants_for_alternative($test, $alt);
//$c1 = (int)ab_tests_total_conversions_for_alternative($test,$alt);
$c2 = (int) ab_tests_total_converted_for_alternative($test, $alt);
if ($p > 0) {
$conv_rate = $c2 / $p * 100;
} else {
$conv_rate = 0;
}
return $conv_rate;
}
/**
* @param unknown_type $test
* @param unknown_type $probability
*/
function ab_tests_score($test, $probability = 90)
{
global $ab_tests;
//i am going to create a nice array/mixed type thingy
//that will carry all the results from this function
$result = array();
//get all alternatives for this test
$alts = $ab_tests[$test]['alternatives'];
// echo "<br>alts: "; print_r($alts);
//gather a list of conversion rates for each test
$conversion_rates = array();
foreach ($alts as $alt) {
$conversion_rates[$alt] = ab_test_conversion_rate($test, $alt);
}
arsort($conversion_rates);
$result['sorted_alts'] = $conversion_rates;
// echo "<br>sortedalts: "; print_r($conversion_rates);
//base is the second best result
$base = array_slice($conversion_rates, 1, 1);
$result['base'] = $base;
// echo "<br>base: "; print_r($base);
//calculate z-score for base:
$base_name = array_slice(array_keys($conversion_rates), 1, 1);
$base_name = $base_name[0];
// echo "<br>base name: "; print_r($base_name);
$result['base_name'] = $base_name;
$pc = ab_test_conversion_rate($test, $base_name) / 100;
$nc = (int) ab_tests_total_participants_for_alternative($test, $base_name);
// echo "<br>pc: ". $pc . " nc:" . $nc;
$z_scores = array();
$percentiles = array();
foreach ($conversion_rates as $alt => $rate) {
// echo "<br>rate: "; print_r($alt); echo " "; print_r($rate);
$p = ab_test_conversion_rate($test, $alt) / 100;
$n = (int) ab_tests_total_participants_for_alternative($test, $alt);
//prevent division by zero
$z_scores[$alt] = 0;
$percentiles[$alt] = 0;
if ($n == 0 || $nc == 0) {
continue;
}
//z-score is the difference over the std deviation
//(p - pc) / ((p * (1-p)/n) + (pc * (1-pc)/nc)).abs ** 0.5
$std_deviation = pow(abs($p * (1 - $p) / $n + $pc * (1 - $pc) / $nc), 0.5);
if ($std_deviation == 0) {
continue;
}
$z_scores[$alt] = ($p - $pc) / $std_deviation;
$percentiles[$alt] = convert_z_score_to_percentile(abs($z_scores[$alt]));
}
// echo "<br>z-score: "; print_r($z_scores);
$result['z-scores'] = $z_scores;
$result['percentiles'] = $percentiles;
//find the least converted one that converted more than 0 times
$least = false;
//fast forward to the end
end($conversion_rates);
if (current($conversion_rates) > 0) {
$least['name'] = key($conversion_rates);
$least['rate'] = current($conversion_rates);
} else {
//keep rewinding until you find one
while (prev($conversion_rates) !== false && $least !== false) {
if (current($conversion_rates) > 0) {
$least['name'] = key($conversion_rates);
$least['rate'] = current($conversion_rates);
}
}
}
// echo "<br>least: "; print_r($least);
$result['least'] = $least;
$differences = array();
foreach ($conversion_rates as $alt => $rate) {
$c1 = ab_test_conversion_rate($test, $alt);
$c2 = $least['rate'];
// echo "<br>c1: " . $c1 . " c2: " . $c2;
$differences[$alt] = $c1 - $c2;
}
// echo "<br>differences: "; print_r($differences);
$result['differences'] = $differences;
$best = array_slice(array_keys($conversion_rates), 0, 1);
$best = $best[0];
$result['best'] = $best;
// echo "<br>best: "; print_r($best);
//print_r($result);
return $result;
}
echo "<P class=\"indent\" style='color: #556; font-size: 12px'>" . $test['description'];
if ($forced_alternative != null) {
//echo "<P class=\"indent\" style='color: #999; font-size: 15px; margin-top: 12px'>" . "Currently forced to show option <u style='color: #666'>$forced_alternative</u> for all participants";
/*echo ' <a href="?force=true&test=' . $test['name'] . '&alt=' . "!!null!!" . '" class="red-button pcb">
<span style="color: black;">Clear</span>
</a>'; */
}
$j = 0;
$a = array();
$total_converted = 0;
$total_conversions = 0;
$total_particants = 0;
$array_of_conversion_rates = array();
echo "<div class=\"alternatives\">";
foreach ($alternatives as $alt) {
$p = $a[$alt]['participants'] = (int) ab_tests_total_participants_for_alternative($name, $alt);
$c1 = $a[$alt]['conversions'] = (int) ab_tests_total_conversions_for_alternative($name, $alt);
$c2 = $a[$alt]['converted'] = (int) ab_tests_total_converted_for_alternative($name, $alt);
if ($p > 0) {
$conv_rate = $c2 / $p * 100;
} else {
$conv_rate = 0;
}
$conv_rate = round($conv_rate, 3);
$array_of_conversion_rates[] = array($j + 1, $conv_rate);
echo "<h3>Alternative <span class=\"alternative\">" . $alt . "</span>:";
if ($forced_alternative != $alt) {
echo ' <a href="?force=true&test=' . urlencode($test['name']) . '&alt=' . urlencode($alt) . '#' . urlencode($name) . '" class="grey-button pcb">
<span style="color: #666;">Show Always</span>
</a>';
} else {
