Table 7. The Result of T Test After Treatment No. Result Science-program class XI 2 (Learning by using smartphones) Science-program class XI 3 (Learning without using smartphones) 1. Average score (X) 82.20 75.40 2. Variance 35.16 27.50 4. tcalculation 4.30 5. ttabulation 2.01 Sources: Research Findings (2014) Vandalita M.M. Rambitan et al. The Effect of Smartphone on Students’ Critical Thinking Skill in Relation to the Concept of Biodiversity. American Journal of Educational Research, 2015, Vol. 3, No. 2, 243-249. doi:10.12691/education-3-2-18 © The Author(s) 2015. Published by Science and Education Publishing.