There are 8 watermelons, and their weights are 5.5 kg, 3.9 kg, 12 kg, 4.9 kg, 5.1 kg, 5.1 kg, 9.4 kg, and 1.5 kg. What is the median weight of these watermelons in kg?
有8个西瓜，它们的重量分别是5.5千克、3.9千克、12千克、4.9千克、5.1千克、5.1千克、9.4千克、1.5千克，这些西瓜重量的中位数是多少千克
<gadget id="calculator">5.1 + 5.1</gadget>
<output>10.2</output>

<gadget id="calculator">10.2 / 2</gadget>
<output>5.1</output>

<result>5.1</result>