5. The presence of harmful insects in farm fields is detected by erecting boards
ID: 3241098 • Letter: 5
Question
5. The presence of harmful insects in farm fields is detected by erecting boards covered with a sticky material and then examining the insects trapped on the board. To investigate which colors are most attractive to cereal leaf beetles, researchers placed six boards of each of four colors in a field of oats in July. The table below gives data on the number of cereal leaf beetles trapped. Color Insects trapped Lemon yellow 45 59 48 46 38 47 White 21 12 14 17 13 17 Green 37 32 15 25 39 41 Blue 16 11 20 21 14 7
a. Is there a significant difference in the average numbers of leaf beetles trapped among the 4 colors? The level of significance is set at 5%. Please carry out the hypothesis testing by setting up null and alternate hypothesis.
b. If the null hypothesis is rejected in part (a), what can you further conclude as to which group(s) has different averages than others? However, it the null hypothesis is not rejected in part (a), what does it mean in the context of the problem.
Explanation / Answer
answer
Computations can be made using ANOVA(L1,L2,L3,L4) in the STAT Tests menu, place data on the 4 lists first. H 0 :?1=?2=?3=?4 H a : not all means are equal
F=30.55
pv= 1.15?10?7
Reject null, there is evidence that some colors attract more leaf beetles than other
Source of Variation SS df MS F P-value Between Groups 4218.46 3 1406.15 30.55 1.15?10?7 Within Groups 920.5 20 46.025 Total 5138.96 23Related Questions
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