Tractor in confined areas. The most common variation of the classic farm tractor is the hoe, also called a hoe-loader. As the name implies, it has a loader assembly on the front and a backhoe on the back. Backhoes attach to a three-point hitch on farm or industrial tractors. Industrial tractors are often heavier in construction, particularly with regards to the use of steel grill for protection from rocks and the use of construction tires. When the backhoe is permanently attached, the machine usually has a seat that can swivel to the rear to face the hoe controls. Removable backhoe attachments
Sum of normally distributed random variables Sum of normally distributed random variables In probability theory, calculation of the sum of normally distributed random variables is an instance of the arithmetic of random variables, which can be quite complex based on the probability distributions of the random variables involved and their relationships. This is not to be confused with the sum of normal distributions which forms a mixture distribution. If "X" and "Y" are independent random variables that are normally distributed (and therefore also jointly so), then their sum is also normally distributed. i.e., if then This means that the sum of two independent normally distributed random