Answer to Question #67846 in Statistics and Probability for FATIN SYLVESTER

Question

In a study of reaction times of horses to a specic stimulus, an animal trainer
selected two samples of horses and measured their reaction times to the same
stimulus. The animal trainer obtained the following data, given in seconds.
Younger Horses Older Horses
2.8 2.3 4.5 3.0 2.6 5.3 3.2 5.1 4.7 5.4 5.6 5.4 3.1 5.2
4.0 3.3 4.8 3.1 4.0 2.7 3.2 4.4 4.5 4.4 4.8 6.3 3.3 4.7
4.7 5.8 6.1 2.3 4.5 2.9 4.1 4.8 4.1 5.5 4.9 5.2 5.4 5.4
3.3 3.3 3.8 5.7 4.5 4.5 4.4 4.6 5.1 4.7 5.2 5.1 4.8 3.2
2.4 5.3 3.9 5.4 3.2 3.2 2.5 3.8 6.0 5.3 4.7 4.8 2.6 3.9
3.1 4.0 4.8 3.2 2.4 2.6 3.5 5.9 4.8 4.1 5.3 6.0 4.6 4.6

(a) Construct a grouped frequency distribution for these data using 6 classes
and a class width of 0.7. Use the lowest value as the starting point.

(b) Find the variance for the two groups of horses.