diff --git a/app/models/tv.rb b/app/models/tv.rb
index fa623c80..6d0f3888 100644
--- a/app/models/tv.rb
+++ b/app/models/tv.rb
@@ -38,12 +38,33 @@ class Tv < Video
   end
 
   has_many :seasons, -> { order_by_season_number }, dependent: :destroy, inverse_of: :tv
+  has_many :episodes, ->  { order_by_episode_number }, through: :seasons
 
   before_validation { broadcast(:tv_validating, self) }
   before_save { broadcast(:tv_saving, self) }
   after_commit { broadcast(:tv_saved, self) }
 
-  def min_max_run_time_seconds
-    (episode_run_time.min * 60)..(episode_run_time.max * 60)
+  def duration_range
+    return if ripped_disk_titles_durations.empty? && episodes_runtime.empty?
+
+    range = round_up_to_nearest_minute(
+      duration_stats.interquartile_range ||
+      episode_runtime_stats.interquartile_range ||
+      DEFAULT_RANGE
+    )
+    average_runtime = duration_stats.weighted_average ||
+                      episode_runtime_stats.weighted_average
+
+    return if average_runtime.nil?
+
+    (average_runtime - range)..(average_runtime + range)
+  end
+
+  def episode_runtime_stats
+    @episode_runtime_stats ||= StatsService.call(episodes_runtime)
+  end
+
+  def episodes_runtime
+    @episodes_runtime ||= episodes.map(&:runtime).uniq.compact_blank
   end
 end
diff --git a/app/models/video.rb b/app/models/video.rb
index 3adc4cb5..8c881d06 100644
--- a/app/models/video.rb
+++ b/app/models/video.rb
@@ -28,6 +28,8 @@
 #
 class Video < ApplicationRecord
   include Wisper::Publisher
+  DEFAULT_RANGE = (60 * 3).seconds # 3 minutes
+
   enum :rating, { 'N/A': 0, NR: 1, 'NC-17': 2, R: 3, 'PG-13': 4, PG: 5, G: 6 }
 
   has_many :disk_titles, dependent: :nullify
@@ -46,7 +48,11 @@ class Video < ApplicationRecord
   validates :title, presence: true
 
   def duration_stats
-    @duration_stats ||= StatsService.call(ripped_disk_titles&.map(&:duration)&.compact_blank || [])
+    @duration_stats ||= StatsService.call(ripped_disk_titles_durations)
+  end
+
+  def ripped_disk_titles_durations
+    @ripped_disk_titles_durations ||= Array.wrap(ripped_disk_titles).map(&:duration).compact_blank
   end
 
   def movie?
@@ -94,4 +100,10 @@ def release_or_air_date
   def plex_name
     release_or_air_date ? "#{title} (#{release_or_air_date.year})" : title
   end
+
+  private
+
+  def round_up_to_nearest_minute(seconds)
+    (seconds.to_f / 60).ceil * 60
+  end
 end
diff --git a/app/services/episode_disk_title_selector_service.rb b/app/services/episode_disk_title_selector_service.rb
index 4b9001ea..174f0639 100644
--- a/app/services/episode_disk_title_selector_service.rb
+++ b/app/services/episode_disk_title_selector_service.rb
@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 class EpisodeDiskTitleSelectorService < ApplicationService
-  DEFAULT_RANGE = (60 * 3).seconds # 3 minutes
-
   Info = Data.define(
     :disk_title,
     :episode,
@@ -53,15 +51,7 @@ def ripped?(episode)
   end
 
   def within_range?(episode, disk_title)
-    runtime_range(episode)&.include?(disk_title.duration)
-  end
-
-  def runtime_range(episode)
-    runtime = episode.tv.duration_stats.weighted_average || episode.runtime
-    range = episode.tv.duration_stats.interquartile_range || DEFAULT_RANGE
-    return if runtime.nil?
-
-    (runtime - range)...(runtime + range)
+    episode.tv.duration_range&.include?(disk_title.duration)
   end
 
   def selected_disk_titles
diff --git a/app/services/stats_service.rb b/app/services/stats_service.rb
index 8fef6453..6dbe17f2 100644
--- a/app/services/stats_service.rb
+++ b/app/services/stats_service.rb
@@ -1,12 +1,15 @@
 # frozen_string_literal: true
 
 class StatsService < ApplicationService
+  Z_SCORE_THRESHOLD = 5
   Info = Data.define(
     :median,
     :weighted_average,
     :median_difference,
     :weighted_average_difference,
-    :interquartile_range
+    :interquartile_range,
+    :z_score,
+    :differences
   )
 
   param :list, Types::Array.of(Types::Coercible::Integer)
@@ -17,7 +20,9 @@ def call
       weighted_average,
       median_difference,
       weighted_average_difference,
-      interquartile_range
+      interquartile_range,
+      z_score,
+      differences
     )
   end
 
@@ -65,6 +70,21 @@ def interquartile_range
     filtered_differences.max
   end
 
+  def z_score
+    return if differences.empty?
+
+    mean = differences.sum.to_f / differences.size
+
+    # Calculate standard deviation
+    variance = differences.map { |x| (x - mean)**2 }.sum / differences.size
+    stdev = Math.sqrt(variance)
+
+    differences.select do |x|
+      z_score = (x - mean) / stdev
+      z_score.abs < Z_SCORE_THRESHOLD
+    end.max
+  end
+
   def calc_weight_average(array, median)
     weights = array.map do |item|
       1.0 / (1.0 + (item - median).abs)
diff --git a/app/views/seasons/show.html.erb b/app/views/seasons/show.html.erb
index f63ec5f6..1dc3354b 100644
--- a/app/views/seasons/show.html.erb
+++ b/app/views/seasons/show.html.erb
@@ -23,9 +23,28 @@
           Title Select
           <small>
             <% if @tv.duration_stats.weighted_average %>
-              (<%= distance_of_time_in_words(@tv.duration_stats.weighted_average - @tv.duration_stats.interquartile_range, 0, include_seconds: false) %>
-              -
-              <%= distance_of_time_in_words(@tv.duration_stats.weighted_average + @tv.duration_stats.interquartile_range, 0, include_seconds: false) %>)
+              (<%= distance_of_time_in_words(@tv.duration_range.min, 0, include_seconds: params[:debug] == 'true') %>
+              ..
+              <%= distance_of_time_in_words(@tv.duration_range.max, 0, include_seconds: params[:debug] == 'true') %>)
+
+              <% if params[:debug] == 'true' %>
+                <br>
+                median: <%= distance_of_time_in_words @tv.duration_stats.median  %>
+                <br>
+                weighted average: <%= distance_of_time_in_words @tv.duration_stats.weighted_average  %>
+                <br>
+                weighted average difference: <%= distance_of_time_in_words @tv.duration_stats.weighted_average_difference %>
+                <br>
+                interquartile range: <%= distance_of_time_in_words(@tv.duration_stats.interquartile_range)  %>
+                <br>
+                median difference: <%= distance_of_time_in_words(@tv.duration_stats.median_difference)  %>
+                <br>
+                z score: <%= distance_of_time_in_words @tv.duration_stats.z_score %>
+                <br>
+                Durations: <%= @tv.ripped_disk_titles_durations.sort.uniq.join(', ') %>
+                <br>
+                Differences: <%= @tv.duration_stats.differences.join(', ') %>
+              <% end %>
             <% end %>
           </small>
         </th>
diff --git a/current_version.txt b/current_version.txt
index eef47253..fa757323 100644
--- a/current_version.txt
+++ b/current_version.txt
@@ -1 +1 @@
-v5.12.0
+v5.13.0
diff --git a/spec/services/episode_disk_title_selector_service_spec.rb b/spec/services/episode_disk_title_selector_service_spec.rb
index 2382bed5..385a83a6 100644
--- a/spec/services/episode_disk_title_selector_service_spec.rb
+++ b/spec/services/episode_disk_title_selector_service_spec.rb
@@ -13,6 +13,11 @@
       let(:disk) { build_stubbed(:disk, disk_titles: [disk_title]) }
       let(:disk_title) { build_stubbed(:disk_title, duration: 10.minutes) }
 
+      before do
+        tv.association(:ripped_disk_titles).target = [disk_title]
+        tv.association(:ripped_disk_titles).loaded!
+      end
+
       it { expect(call.first).to be_a(described_class::Info) }
       it { expect(call.first.disk_title.id).to eq(disk_title.id) }
       it { expect(call.first.episode.id).to eq(episodes.first.id) }
@@ -26,6 +31,11 @@
       let(:disk_title_a) { build_stubbed(:disk_title, duration: 10.minutes) }
       let(:disk_title_b) { build_stubbed(:disk_title, duration: 10.minutes) }
 
+      before do
+        tv.association(:ripped_disk_titles).target = [disk_title_a, disk_title_b]
+        tv.association(:ripped_disk_titles).loaded!
+      end
+
       it { expect(call.first.episode.id).to eq(episodes.first.id) }
       it { expect(call.first.disk_title.id).to eq(disk_title_a.id) }
       it { expect(call.second.episode.id).to eq(episodes.second.id) }
diff --git a/spec/services/stats_service_spec.rb b/spec/services/stats_service_spec.rb
index c038887c..617995b9 100644
--- a/spec/services/stats_service_spec.rb
+++ b/spec/services/stats_service_spec.rb
@@ -8,14 +8,19 @@
 
     context 'when a bunch of values are given' do
       let(:list) { [2579, 2498, 2549, 2575, 2573, 2486, 2518, 2580, 2494, 2577, 2575, 2575, 2577, 2443, 2578, 2441, 2521, 2561, 2580, 2534, 2571, 2565, 5062] }
+      let(:differences) do
+        [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 26, 27, 28, 29, 30, 31, 32, 35, 36, 37, 39, 40, 41, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 67, 71, 73,
+         75, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 89, 91, 92, 93, 94, 106, 108, 118, 120, 122, 124, 128, 130, 132, 134, 135, 136, 137, 138, 139, 2482, 2483, 2484, 2485, 2487, 2489, 2491, 2497, 2501, 2513, 2528, 2541, 2544,
+         2564, 2568, 2576, 2619, 2621]
+      end
 
-      it { is_expected.to eq(described_class::Info.new(2575, 2573.7497394471216, 62.5, 62.79612125669019, 139)) }
+      it { is_expected.to eq(described_class::Info.new(2575, 2573.7497394471216, 62.5, 62.79612125669019, 139, 2621, differences)) }
     end
 
     context 'when nothing is given' do
       let(:list) { [] }
 
-      it { is_expected.to eq(described_class::Info.new(nil, nil, nil, nil, nil)) }
+      it { is_expected.to eq(described_class::Info.new(nil, nil, nil, nil, nil, nil, [])) }
     end
   end
 end