The feeding habits of two species of net-casting spiders arestudied. These speci
ID: 2955245 • Letter: T
Question
The feeding habits of two species of net-casting spiders arestudied. These species, the Dinopis andMenneus, coexist in eastern Australia. One variableof interest is the size of the prey of each species. Is therea difference in average prey size between Dinopis andMenneus based on the data below?
Dinopis prey size (mm)
Menneus prey size (mm)
12.9
11.9
10.2
5.3
10.2
7.1
6.9
7.5
7.4
9.9
10.9
10.3
7.0
14.4
11.0
9.2
10.5
11.3
10.1
8.8
Test of equality of variances:
Ho:
Ha:
Test statistic & value:
p-value:
Statistical conclusion:
Test of means:
Ho:
Ha:
Test statistic & value:
p-value:
Statistical conclusion:
Practical conclusion:
Dinopis prey size (mm)
Menneus prey size (mm)
12.9
11.9
10.2
5.3
10.2
7.1
6.9
7.5
7.4
9.9
10.9
10.3
7.0
14.4
11.0
9.2
10.5
11.3
10.1
8.8
Explanation / Answer
Test of equality of variances:
Ho:1^2 =2^2
Ha:1^2 not equal2^2
Test statistic & value:
F=s1^2/s2^2
=2.514^2/1.897^2
=1.76
p-value:
2*P(F(n1=9, n2=9) >1.76)=0.7937 (check F table)
Statistical conclusion:
Group Dinopis prey size Menneus prey size Mean 10.260 9.020 SD 2.514 1.897 SEM 0.795 0.600 N 10 10Related Questions
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