A Number of Butterfly Species Mate for Hours, and If $$\text { Take-off angle (degrees) }$$

question 16

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, 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
angle of escape are presented below. The investigators considered performing a
hypothesis test to determine if there was evidence that the mean take off angle was
different for singles and pairs. Using a graphical procedure of your choice,
determine if the t-test is appropriate. $$\text { Take-off angle (degrees) }$$
$$\begin{array}{l}\text { Take-off angle (degrees) }\\\begin{array} {lll } \text { Single}&0.4,&1.9,&7.0,&21.7&24.4,&28.0,&28.6,&35.4,&39.9,&40.2,&57.0\\&57.0,&65.0,&68.9\\\\ \text {Paired }&1.0,&8.5,&8.5,&13.9,&14.8,&15.7,&16.6,&25.3,&29.5,&36.0,&44.7\\&47.1,&51.6,&55.8,&73.1,&74.3\\\end{array}\end{array}$$