Cicadas are flying, plant eating insects. One particular species, the 13-year cicadas, spends five juvenile stages in underground borrows. During the 13 years underground, the cicdas grow from approximately the size of a small ant to nearly the size of an adult cicada. The adult body weighs (BW) in frams and wing length (WL) in millimeters are given for three different species of these 13 year cicadas in the following table.
BW WL Specie
.15 28 Tredecila
.29 32 Tredecim
.17 27 Tredecim
.18 30 Tredecula
.39 35 Tredecim
.26 31 Tredecim
.17 29 tredecassini
.16 28 tredecassini
.18 29 Tredecila
.21 27 tredecassini
.15 30 Tredecila
.17 27 Tredecila
.13 27 Tredecassini
.17 29 Tredecassini
.23 30 Tredecassini
.12 22 Tredecim
.14 25 Tredecassini
.14 28 Tredecassini
.28 25 Tredecassini
.12 28 Tredecim
.26 30 Tredecila
.19 30 Tredecila
.20 30 Tredecassini
.14 23 Tredecila
A. Draw a scatter diagram with body weight as the independent variable and wing length as the dependent variable. Find the equation of the line of best fit.
B. Is body weight effective predictor of wing length for a 13 year cicada? Use a .05 level of significance.
C. Give a 90% confidence interval for the mean wing length for all .20 gram cicada body weights.