A tree nursery has been experimenting with fertilizer to increase the growth of seedlings. A sample of 35 two-year old pine trees are grown for three more years with a cake of fertilizer buried in the soil near the trees' roots. A second sample of 35 two-year-old pine trees are grown for three more years under identical conditions (soil, temperature, water) as the first group, but not fertilized. Tree growth is measured over the three-year period with the following results.

Do the data support the theory that the population of trees with the fertilizer grew significantly larger during the period in which they were fertilized than the nonfertilized trees? Use α =.01.

Transcribed Image Text:

Trees with Fertilizer Trees Without Fertilizer n 35 x 38.4 inches o 9.8 inches x23.1 inches ơ2 7.4 inches