Find the middle value of a dataset. Robust to outliers, easy to interpret.
Median is the middle value in a sorted dataset. It divides data into two equal halves: 50% below, 50% above. Also called the 50th percentile.
For odd count: median = middle value
For even count: median = average of two middle values
Why Use Median?
Median vs Mean: Mean assumes normal distribution (sensitive to outliers). Median works with any distribution (resistant to extremes). Compare both to assess skewness.
Arrange all values from smallest to largest. Order matters for finding middle.
Determine if count is odd or even. This decides whether median is a single value or average.
Odd count: pick center value. Even count: identify two middle values at positions n/2 and n/2+1.
For even count, average the two middle values. For odd, median is already found.
Dataset (unsorted): 5, 7, 2, 8, 4 Step 1: Sort Sorted: [2, 4, 5, 7, 8] Step 2: Count n = 5 (odd number) Step 3: Find middle Position = (5 + 1) / 2 = 3rd value 3rd value in [2, 4, 5, 7, 8] = 5 Result: Median = 5
Dataset (unsorted): 3, 1, 4, 2 Step 1: Sort Sorted: [1, 2, 3, 4] Step 2: Count n = 4 (even number) Step 3: Find two middles Positions: 2nd and 3rd values Values: 2 and 3 Step 4: Average Median = (2 + 3) / 2 = 2.5
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