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 [[alternative HTML version deleted]]
On 6/11/2008, at 11:13 AM, Lucas Eggert wrote:> 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 ><snip>> 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 singul?r > > 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!Look at the last line of your data frame. cheers, Rolf Turner ###################################################################### Attention: This e-mail message is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. Any views or opinions presented are solely those of the author. This e-mail has been scanned and cleared by MailMarshal www.marshalsoftware.com ######################################################################