A Number of Butterfly Species Mate for Hours, and If

Essay

A number of butterfly species mate for hours, and if a mating couple is disturbed, one
of the butterflies is responsible for flying, carrying its partner with it. Not only are
mating pairs more noticeable to predators, but the added weight may hamper the
flight during escape. Random samples of Green-veined White (Pieris napi)
butterflies were the subjects of a Swedish study to investigate the escape flights of
single butterflies and of mating pairs when exposed to a predator. Data on the initial
takeoff escape velocities are presented below. The investigators considered
performing a hypothesis test to determine if there was evidence that the mean take off
escape velocity was different for singles and pairs. Using a graphical procedure of
your choice, determine if the t-test is appropriate. $$\begin{array}{l}\text { Escape velocity (m/sec) }\\\text { Single } 0.76 , \quad 0.89 , \quad 0.94,1.01,1.09,1.11,1.12,1.17,1.19,1.20,1.29\\1.34 , \quad 1.42 , \quad 1.54\\\\\text { Paired } 0.58,0.58,0.76,0.86,0.95,0.97,1.03,1.05,1.14,1.35,1.38\\1.61 , \quad 1.62 , \quad 1.77 , \quad 2.29 , \quad 2.29\end{array}$$