Question

4. A study was made at the Experimental Station in to determine the relationship between roots and fungi during which minerals are transferred from fungi to roots and sugars are transferred from roots to fungi. Twenty mahogany seeds were taken with the fungus Pisolithus tinctorus and grown in a nursery. All the seeds were planted in the same type of soil and received the same amount of water and sun. Half of them received nitrogen (370 ppm) and the other half did not receive nitrogen. After 150 days, the leaves were weighed in grams. Assume that the variances are equal.

No nitrogen	Nitrogen
.32 .53 .28 .37 .47 .43 .36 .42 .38 .43	.26 .43 .47 .49 .52 .75 .79 .86 .62 .46

Do a hypothesis test to test if the difference of the averages with an alpha of 10%.

Answer 1

The null and alternative hypothesis:

H0: There is no significant difference of the averages of leaves weight between Nitrogen and without nitrogen.

H1: There is significant difference of the averages of leaves weight between Nitrogen and without nitrogen

The value of test statistic is:

t= -2.619

The p-value = 0.017

Conclusion: The p-value of t test is less than 0.10. Hence we reject null hypothesis at 10% level of significance and conclude that there is significant difference of the averages of leaves weight between Nitrogen and without nitrogen.