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.
Like other infections of the lungs, tuberculosis can trigger coughing. Symptoms of TB include: a cough that lasts at least three weeks, coughing up discharge or sputum from the lungs that looks dark or bloody, and pain in the chest. Other symptoms can include weight loss, loss of appetite, mild fever, weakness or fatigue, chills, and sweating at night.