Solved: It has been shown that the fertilizer magnesium

Chapter 13, Problem 13.7

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It has been shown that the fertilizer magnesium ammonium phosphate, MgNH4PO4, is an eective supplier of the nutrients necessary for plant growth. The compounds supplied by this fertilizer are highly soluble in water, allowing the fertilizer to be applied directly on the soil surface or mixed with the growth substrate during the potting process. A study on the Eect of Magnesium Ammonium Phosphate on Height of Chrysanthemums was conducted at George Mason University to determine a possible optimum level of fertilization, based on the enhanced vertical growth response of the chrysanthemums. Forty chrysanthemum seedlings were divided into four groups, each containing 10 plants. Each was planted in a similar pot containing a uniform growth medium. To each group of plants an increasing concentration of MgNH4PO4, measured in grams per bushel, was added. The four groups of plants were grown under uniform conditions in a greenhouse for a period of four weeks. The treatments and the respective changes in heights, measured in centimeters, are shown next. Treatment 50 g/bu 100 g/bu 200 g/bu 400 g/bu 13.2 12.4 16.0 12.6 7.8 14.4 21.0 14.8 12.8 17.2 14.8 13.0 20.0 15.8 19.1 15.8 13.0 14.0 14.0 23.6 17.0 27.0 18.0 26.0 14.2 21.6 14.0 17.0 19.6 18.0 21.1 22.0 15.0 20.0 22.2 24.4 20.2 23.2 25.0 18.2 Can we conclude at the 0.05 level of signicance that dierent concentrations of MgNH4PO4 aect the average attained height of chrysanthemums? How much MgNH4PO4 appears to be best?