I am a beginner in statistics, and I want to learn machine learning :). Therefore, I have gathered some sample data to practice. But, the problem is I want to create a feature (or attribute), which is common for every entity. But, this feature is observed and measured for entity X in Y meters and Z seconds, and for entity W in M meters and L seconds, and there are many observations like described before. Which algorithm should I apply to create a common feature for all entities? BTW, I am using WEKA.