ALCOHOLISM AND BEHAVIOR OF WHITE RATS 



259 



of trials surely significant; the nearest approach to three times 

 the probable error is 2.77 times, for oinitting the first day; then 

 comes the first half of training, training and retention, and train- 

 ing with differences 2.49, 2.09, and 1.89 times their probable 

 errors; for the other two groups of trials the differences are less 

 than half as large as their probable errors. When the standard 

 deviation of the averages for each day are calculated (table 12) 

 the tests are proved the more variable on the first six days of 

 training and on the second and fourth days of retention; but 



TABLE 11 

 Standard deviations of the distance averages for each rat when all strains and both sexes 

 are put together for the six groupings of the trials, calculated from the data given in 

 table B in the appendix. The differences, their probable errors, and the differences 

 divided by their probable errors are given. Plus signs indicate that the standard 

 deviations of the tests are greater than those of the controls; minus signs, that the 

 standard deviations of the controls are larger. Although there are no fully signifi- 

 cant differences, the differences that are over twice their probable errors are all in 

 the direction of greater variability for the tests 



1 Omitting rat 1211. 



when compared with their probable errors, the only significant 

 difference is found on the second day of retention. On the 

 seventh day of training the controls are significantly more 

 variable. There does not seem to be any general difference in 

 the variability of the averages of the tests and controls based 

 on distance, although five of the comparisons show greater 

 variabihty for the tests by differences twice their probable errors; 

 there are only two significant differences, one showing the con- 

 trols more variable, the other showing the tests more variable. 

 Averages for each of the thirty-six trials in training and reten- 

 tion have been obtained and the tests and controls compared on 



