Dear Experts,
I am new to R and unfortunately cannot start with a simply statistical
analysis:
I manually determined the volume of the right and left hippocampus in
a group of meditators and in a group of controls. My data-sheet looks
as follows:
observation subject group age gender hemisphere volume
1 am04 m 25 f left 3.637
2 am04 m 25 f right 3.713
3 ao08 m 47 m left 3.715
4 ao08 m 47 m right 3.702
5 as11 m 43 f left 3.912
6 as11 m 43 f right 4.438
7 bn02 c 30 f left 4.497
8 bn02 c 30 f right 4.333
9 ca15 c 46 m left 3.346
10 ca15 c 46 m right 3.779
11 cd13 m 41 m left 4.167
12 cd13 m 41 m right 4.184
13 dk09 m 45 m left 4.289
14 dk09 m 45 m right 4.457
15 dm08 c 42 m left 4.084
16 dm08 c 42 m right 3.572
17 donf55 c 47 m left 4.006
18 donf55 c 47 m right 4.211
19 dr01 c 28 m left 3.717
20 dr01 c 28 m right 3.660
21 ds17 m 46 m left 4.140
22 ds17 m 46 m right 4.157
23 dts14 m 30 m left 4.830
24 dts14 m 30 m right 5.081
25 eg19 m 46 f left 4.679
26 eg19 m 46 f right 4.123
27 em12 m 33 m left 4.183
28 em12 m 33 m right 4.671
29 ew10 m 48 m left 4.074
30 ew10 m 48 m right 4.133
31 harp74 c 29 f left 4.449
32 harp74 c 29 f right 4.505
33 ih18 m 26 f left 4.859
34 ih18 m 26 f right 4.635
35 jk20 c 26 f left 4.765
36 jk20 c 26 f right 4.582
37 jl22 m 29 m left 4.798
38 jl22 m 29 m right 4.970
39 jm05 c 24 m left 4.177
40 jm05 c 24 m right 3.878
41 jp16 c 49 m left 4.541
42 jp16 c 49 m right 4.468
43 kr16 m 28 f left 5.193
44 kr16 m 28 f right 5.367
45 ln06 m 31 f left 5.283
46 ln06 m 31 f right 5.971
47 ls06 c 29 f left 4.462
48 ls06 c 29 f right 4.517
49 md02 m 50 m left 4.733
50 md02 m 50 m right 4.456
51 rp19 c 33 m left 4.572
52 rp19 c 33 m right 4.270
53 rs20 m 49 m left 5.410
54 rs20 m 49 m right 5.275
55 sinj55 c 49 f left 4.634
56 sinj55 c 49 f right 4.883
57 sm21 m 42 f left 4.499
58 sm21 m 42 f right 4.317
59 sw04 c 34 m left 3.956
60 sw04 c 34 m right 4.303
61 sy15 m 40 m left 4.429
62 sy15 m 40 m right 4.550
63 ts14 c 46 m left 4.233
64 ts14 c 46 m right 4.568
65 wi18 c 35 m left 5.101
66 wi18 c 35 m right 5.317
67 ws01 m 30 m left 5.221
68 ws01 m 30 m right 5.258
69 zz03 m 35 m left 4.446
70 zz03 m 35 m 4.446 4.627
My attempt to compute the according statistic was:
aov = aov(volume~(hemisphere*group)+Error(subject/hemisphere)+
(group),input)
but with this I got the following error message:
In aov(volume ~ (hemisphere * group) + Error(subject/hemisphere) + :
Error() Modell ist singulär
I could not figure out what I did wrong. Furthermore, in the next step
I would like to use gender and age as additional covariates in the
model, but I am not sure how to do this either.
Any help would be very much appreciated!
Thank you,
Sincerely,
Lucas Eggert
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