A Biological Question - Which fertilizer is better: brand A or brand B?

My Hypothesis: brand B, because I have seen it advertized on TV.

The Experiment:

The Data
WeekPlant # 1 - cmPlant # 2 - cmPlant # 3 - cm
1121212
2121312
3131413
4131513
5141614
6141615
7151616
8151617