## Swim Maze Testing in Rat Pups

### Part 2 - Table 2

Impregnated dam rats were allocated randomly to receive either 0, 3.125, 6.25, or 12.5 mg/kg of an investigational compound. One male and one female pup from each resulting litter was evaluated for Single-T Swim maze performance. The swim maze is shaped like the capital letter "T". The entry channel is the "base" of the T and the "cross bar" is the exit channel. The swim maze is filled with water. At each end of the exit channel there is an exit ramp by which rat pups may escape from the swim maze. There are two trials.

In Trial 1, each rat pup is placed in the water at the beginning of the entry channel and allowed to swim towards the exit channel, turn right or left, and escape by the ramp at either end of the exit channel. The ramp used to escape remains. The ramp located at the opposite end of the exit channel is removed. Subsequently, the pup is repeatedly placed back into the water in the entry channel and allowed to swim the Single T swim maze in an effort to escape successfully three consecutive times. A successful escape occurs when the rat pup swims the length of the entry channel, enters the exit channel, turns, swims directly to the chosen ramp location, and exits the swim maze.

In the second trial, the exit ramp is moved from the chosen end of the exit channel to the opposite end. Once again the rat pup is repeatedly placed into the Single T swim maze until three successful escapes are accomplished in the new exit ramp location.

• Are the number of swims until three successful escapes dose related?
• Is there a difference between sexes?
• Is there a relationship between trials 1 and 2?
• Are the individual swimming attempts independent?
• Is the probability of success constant?
• Could we model these data with the Negative Binomial Distribution of the order k?

Part 2 - Table 2

Swim Maze Testing in Rat Pups

Number of Swims Until Three Consecutive Escapes

 Dose Litter Sex (mg/kg) Trial 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 M 0 1 9 3 9 4 5 6 5 6 4 6 7 9 3 5 6 8 4 5 3 (a) 2 12 7 4 4 8 18 6 7 5 6 7 13 8 13 8 4 4 5 4 (a) 3.125 1 3 8 4 3 4 3 4 4 7 5 5 10 4 3 6 11 10 6 4 5 2 11 7 6 8 8 6 14 7 7 4 4 5 7 5 4 4 8 8 5 4 6.25 1 8 9 4 3 12 11 4 4 5 7 8 5 5 5 4 3 5 10 5 (a) 2 5 10 7 7 7 5 6 7 8 4 8 5 4 9 12 4 13 7 7 (a) 12.5 1 8 8 6 6 6 6 3 5 4 4 6 6 12 3 3 8 3 6 9 (a) 2 8 8 10 8 7 7 6 10 4 6 10 7 6 10 4 6 8 6 5 (a) F 0 1 5 8 9 6 15 6 5 11 4 6 3 6 4 9 3 6 4 6 6 (a) 2 8 5 10 19 7 7 6 7 4 9 4 9 9 5 6 5 11 6 5 (a) 3.125 1 6 5 4 4 8 3 4 11 3 7 7 4 4 6 9 3 6 5 6 6 2 8 6 5 9 8 7 6 14 7 8 11 10 8 9 15 11 4 7 6 6 6.25 1 3 3 3 3 10 4 4 4 3 3 7 5 3 5 3 7 6 3 6 (a) 2 15 7 6 8 4 5 11 5 6 8 47 9 6 7 7 6 4 8 4 (a) 12.5 1 5 4 7 3 5 3 8 10 4 4 5 3 5 8 4 12 6 4 5 (a) 2 9 4 5 6 7 10 4 4 9 5 7 5 6 14 4 4 3 9 5 (a)

(a) N=19 litters only

### Source:

Bradstreet, T.E. (1992) "Favorite Data Sets from Early Phases of Drug Research - Part 2." Proceedings of the Section on Statistical Education of the American Statistical Association.