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.
Causes of tuberculosis. Tuberculosis (TB) is caused by a type of bacterium called Mycobacterium tuberculosis. The condition is spread when a person with an active TB infection in their lungs coughs or sneezes and someone else inhales the expelled droplets, which contain TB bacteria. Although it is spread in a similar way to a cold or the flu, TB is not as contagious.