For the rotarod, even though BECs were equivalent for those mice tested first and second, the results were more complex. A preliminary analysis of mean trial latencies showed a trend toward significant effects of test order [F(1,53) = 3.6, p = .07]. Those mice tested first on the rotarod performed more poorly than those tested after balance beam testing, and there also was a trend toward a significant interaction of group and test order [F(1,53) = 2.9, p = .10]. We therefore performed separate analyses of the mice tested first and those tested second on the rotarod. In all analyses, performance improved significantly over trials, assessed by calculating the difference between Trial 1 and Trial 3 latencies. This improvement index was slightly skewed to the left, so we performed a reflection of the data (largest score +1) and then took the square root of the reflected difference score to obtain a normal distribution (16). Analyses of these transformed data showed that ethanol drinking in the dark led to nearly significant impairment for those mice tested second on the rotarod [F(1,25) = 3.96, p = .058] but not in those tested first [F(1,28) = .5, p = .47; see Figure 8].
