To assess the effects of two different strains of the tobacco mosaic virus, W. Youden and H. Beale randomly selected eight tobacco leaves. half of each leaf was subjected to one of the strains of tobacco mosaic virus and the other half to the other strain. The researchers then counted the number of local lesions apparent on each half of each leaf. The results of their study were published in the paper "A Statistical Study of the Local Lesion Method for Estimating Tobacco Mosaic Virus" (Contributions to Boyce Thompson Institute, Vol. 6, p. 437). Here are the data.

Suppose that you want to perform a hypothesis test to determine whether a difference exists between the mean numbers of local lesions resulting from the two viral strains. Conduct preliminary graphical analyses to decide whether applying the paired t-test is reasonable. Explain your decision.

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Leaf 1 2 3 4 5 6 7 8 Virus 1 31 20 18 17 98 10 7 Virus 2 18 17 14 1 10 7 5 6