The males of stalk-eyed flies (Cyrtodiopsis dalmanni) have long eye stalks. The females sometimes use the length of these eye stalks to choose mates. An experiment was carried out in which two groups of male "stalkies" were reared on different foods. (David et al. 2000). One group was fed corn (considered a high-quality food), while the other was feed cotton wool (a food of substantially lower quality). Each male was raised singly and so represents an independent sampling unit. The eye spans (the distance between the eyes) were recorded in millimeters. The data is summarized as follows, where the corn-fed flies represent treatment group 1 and the cotton-fed flies represent treatment group 2.

Mean (mm) Variance (mm2) Sample size, n

Corn diet (group 1)

2.24 0.0874 28

Cotton diet (group 2)

1.55 0.00374 22

Using Welch's t-test, solve for t and round your answer to two decimal places.