If no correlation exists between the variables, the points appear randomly scattered on the coordinate plane. If a large correlation exists, the points concentrate near a straight line. Scatter plots are useful data visualization tools for illustrating a trend. If the vertical (or y-axis) variable increases as the horizontal (or x-axis) variable increases, the correlation is positive.
Whiplash Whiplash, a severe neck injury, can cause stiffness and pain in the neck, headache, dizziness, and more. Aortic stenosis Aortic stenosis is a condition of the heart causing shortness of breath, dizziness, or chest pain.
About Tension-Type Headache. Tension-type headache, previously called muscle contraction headache, is the most common type of headache. Its name indicates the role of stress and mental or emotional conflict in triggering the pain and contracting muscles in the neck, face, scalp, and jaw. Tension-type headaches may also be caused by jaw clenching, intense work, missed meals, depression, anxiety, or too little sleep.