Question

Is fertilizer A more effective than fertilizer B ? Ten equally sized plots of land were planted with lucerne (a clover-like plant used for animal fodder). Five randomly selected plots were fertilised with fertilizer A and remaining Five plots were with fertilizer B. Plant growth (in cm) over specified period of time was recorded in following table

Fertilizer A. | Fertilizer B

10 | 8

16 | 4

6 | 7

7 | 3

5 | 5

If we assume that the growth in cms are normally distributed. Can we concluded at the 5% significant level Fertilizer A is more effective than fertilizer B?

In excel format.

Answer 1

Let population 1: Fertilizer A

population 2: Fertilizer B

The mean and SD for sample 1:

Following table shows the calculations:

	X1	(X1-mean)^2
	10	1.44
	16	51.84
	6	7.84
	7	3.24
	5	14.44
Total	44	78.8

The mean and SD for sample 2:

Following table shows the calculations:

	X2	(X2-mean)^2
	8	6.76
	4	1.96
	7	2.56
	3	5.76
	5	0.16
Total	27	17.2

Conclusion: We can conclude that Fertilizer A is more effective than fertilizer B.

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Following is the output of t test generated by excel: