x 2 sum - The total of each value in the x column squared and then added together. y 2 sum - The total of each value in the y column squared and then added together. N - The total number of elements (or trials in your experiment).
Patients with tuberculosis of the lungs have a prolonged illness with fever, cough, night-sweats, weight loss and may occasionally cough up blood. As the disease progresses, symptoms get worse and shortness of breath ensues. Untreated disease can be fatal.
In the United States, the majority of tuberculosis (TB) cases in people are caused by Mycobacterium tuberculosis (M. tuberculosis). Mycobacterium bovis (M. bovis) is another mycobacterium that can cause TB disease in people.