compute std for packaging stats

openfoodfacts · Jun 28, 2023 · 9575072 · 9575072
1 parent 33f74ce
commit 9575072
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diff --git a/lib/ProductOpener/PackagingStats.pm b/lib/ProductOpener/PackagingStats.pm
@@ -226,6 +226,7 @@ sub compute_stats_for_all_weights ($packagings_stats_ref) {
 =head2 compute_stats_for_values ($values_ref)
 
 Compute stats for values (e.g. weights or percent) passed in $values_ref->{values} in comma delimited format
+The values are converted to an array.
 
 =cut
 
@@ -245,7 +246,15 @@ sub compute_stats_for_values ($values_ref) {
 	}
 
 	if ($values_ref->{n} > 0) {
+		# Compute the mean
 		$values_ref->{mean} = $values_ref->{sum} / $values_ref->{n};
+
+		# Compute the standard deviation
+		my $sum_of_square_differences = 0;
+		foreach my $value (@{$values_ref->{values}}) {
+			$sum_of_square_differences += ($value - $values_ref->{mean}) * ($value - $values_ref->{mean});
+		}
+		$values_ref->{std} = sqrt($sum_of_square_differences / (scalar @{$values_ref->{values}}));
 	}
 
 	return;

diff --git a/...ected_test_results/packaging_stats/compute_stats_for_all_materials_1_glass_1_plastic.json b/...ected_test_results/packaging_stats/compute_stats_for_all_materials_1_glass_1_plastic.json
@@ -9,6 +9,7 @@
                      "products_percent" : {
                         "mean" : 100,
                         "n" : 2,
+                        "std" : 0,
                         "sum" : 200,
                         "values" : [
                            "100",
@@ -18,6 +19,7 @@
                      "weight_100g" : {
                         "mean" : 550,
                         "n" : 2,
+                        "std" : 450,
                         "sum" : 1100,
                         "values" : [
                            "1000",
@@ -27,6 +29,7 @@
                      "weight_100g_material" : {
                         "mean" : 550,
                         "n" : 2,
+                        "std" : 450,
                         "sum" : 1100,
                         "values" : [
                            "1000",
@@ -39,6 +42,7 @@
                      "products_percent" : {
                         "mean" : 50,
                         "n" : 2,
+                        "std" : 50,
                         "sum" : 100,
                         "values" : [
                            "100",
@@ -48,6 +52,7 @@
                      "weight_100g" : {
                         "mean" : 500,
                         "n" : 2,
+                        "std" : 500,
                         "sum" : 1000,
                         "values" : [
                            "1000",
@@ -57,6 +62,7 @@
                      "weight_100g_material" : {
                         "mean" : 1000,
                         "n" : 1,
+                        "std" : 0,
                         "sum" : 1000,
                         "values" : [
                            "1000"
@@ -67,6 +73,7 @@
                      "products_percent" : {
                         "mean" : 0,
                         "n" : 2,
+                        "std" : 0,
                         "sum" : 0,
                         "values" : [
                            "0",
@@ -76,6 +83,7 @@
                      "weight_100g" : {
                         "mean" : 0,
                         "n" : 2,
+                        "std" : 0,
                         "sum" : 0,
                         "values" : [
                            "0",
@@ -87,6 +95,7 @@
                      "products_percent" : {
                         "mean" : 0,
                         "n" : 2,
+                        "std" : 0,
                         "sum" : 0,
                         "values" : [
                            "0",
@@ -96,6 +105,7 @@
                      "weight_100g" : {
                         "mean" : 0,
                         "n" : 2,
+                        "std" : 0,
                         "sum" : 0,
                         "values" : [
                            "0",
@@ -108,6 +118,7 @@
                      "products_percent" : {
                         "mean" : 50,
                         "n" : 2,
+                        "std" : 50,
                         "sum" : 100,
                         "values" : [
                            "0",
@@ -117,6 +128,7 @@
                      "weight_100g" : {
                         "mean" : 50,
                         "n" : 2,
+                        "std" : 50,
                         "sum" : 100,
                         "values" : [
                            "0",
@@ -126,6 +138,7 @@
                      "weight_100g_material" : {
                         "mean" : 100,
                         "n" : 1,
+                        "std" : 0,
                         "sum" : 100,
                         "values" : [
                            "100"
@@ -136,6 +149,7 @@
                      "products_percent" : {
                         "mean" : 0,
                         "n" : 2,
+                        "std" : 0,
                         "sum" : 0,
                         "values" : [
                            "0",
@@ -145,6 +159,7 @@
                      "weight_100g" : {
                         "mean" : 0,
                         "n" : 2,
+                        "std" : 0,
                         "sum" : 0,
                         "values" : [
                            "0",