lib/easystats.rb in easystats-0.0.1 vs lib/easystats.rb in easystats-0.0.2

@@ -1,21 +1,26 @@
 class Easystats
   def self
 
   end
 
-  # take in an array of numbers and calculate the mean (average)
-  def mean(data)
+  # take in an array of numbers and calculate the sum
+  def sum(data)
     sum_of_numbers = 0
 
     data.each do |num|
       sum_of_numbers += num
     end
 
-    sum_of_numbers / data.count
+    sum_of_numbers
   end
 
+  # take in an array of numbers and calculate the mean (average)
+  def mean(data)
+    self.sum(data) / data.count
+  end
+
   # take in an array of numbers and calculate the standard deviation
   def standard_deviation(data)
     average = self.mean(data)
     deviations = Array.new
     sum_of_deviations = 0
@@ -27,8 +32,35 @@
     deviations.each do |num|
       sum_of_deviations += num
     end
 
     Math::sqrt(sum_of_deviations / (data.count-1))
+  end
+
+  # take in the array of numbers and calculate the median
+  def median(data)
+    halfway = data.count / 2
+
+    # Sort the array
+    data = data.sort
+
+    # The median will be different based on the number of numbers in the array
+    # If there is an even number in the array
+    if(data.count % 2) == 0
+      median = (data[halfway] + data[halfway-1]) / 2.0
+
+    # Else, there is an odd number in the array
+    else
+      median = data[halfway]
+    end
+
+    median
+  end
+
+  # take in an array of numbers and calculate the range
+  def range(data)
+    # Sort the array
+    data = data.sort
+    data[data.count-1] - data[0]
   end
 end