The Mastic tree (Pistacia lentiscus) is used in reforestation efforts in southeastern Spain. The article “Nutrient Deprivation Improves Field Performance of Woody Seedlings in a Degraded Semi-arid Shrubland” (R. Trubata, J. Cortina, and A. Vilagrosaa, Ecological Engineering, 2011:1164–1173) presents a study that investigated the effect of adding slow-release fertilizer to the usual solution on the growth of trees. Following are the heights, in cm, of 10 trees grown with the usual fertilizer (the control group), and 10 trees grown with the slow-release fertilizer (treatment). These data are consistent with the mean and standard deviation reported in the article. Can you conclude that the mean height of plants grown with slow-release fertilizer is greater than that of plants with the usual fertilizer?
Usual 17.3 22.0 19.5 18.7 19.5
18.5 18.6 20.3 20.3 20.3
Slow-release 25.2 23.2 25.2 26.2 25.0
25.5 25.2 24.1 24.8 23.6
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