A researcher wants to know the average growth of a certain plant one week after germination. The greenhouse where he grows plants has 12 trays with 36 plants in each tray l. He picks one tray from the greenhouse and measures the heights of each plant. The results are shown in the dot plot. When analyzing the data, he sees that the heights of the plants are clustered around in 2 in. Could this be the result of bias in his sampling method? Explain. ​