On average among OECD countries, there are about 14 students. per teacher at the secondary level (Table D2.2). As the differences in student-teacher ratios indicate, there are fewer full-time equivalent students per full-. time equivalent teachers at the secondary level than at the primary level of education.
Causes of Lower Back Pain. Home/Conditions/Causes of Lower Back Pain. Pain in the lower back has a multitude of causes. The discs, facets, pars interarticularis, sacroiliac joints, hip joints and nerves can all cause a form of lower back pain.
Common Causes of Back Pain. 1  Whether your back pain is chronic or acute, it's possible to find some relief. 2  Weight. 3  Overweight people have an increased risk for back pain.  Sedentary 1  lifestyle. Lack of exercise can cause or worsen back pain because of increased stiffness and weakened muscles.  Sitting posture.